From Europe to the Alhambra: The Origins of the Conservation and Restoration of Historic Architecture to the Preservation of the Alhambra Palatine City

Abstract

The present article aims to provide a complete overview of the concepts, regulations, and criteria developed in Europe, in addition to an analysis of their consequences in the Alhambra Palatine City from its Christian period (1492) until the arrival of Leopoldo Torres Balbás (1923). Considering that the first step towards a complete understanding and evaluation of a cultural heritage site is the recognition of the general context before its particularities, this study presents a dual focus, systematically following the chronological progression of the events. Through an exhaustive historical analysis based on the most relevant bibliographical and documentary sources in the discipline of Conservation-Restoration of Historic Buildings, this article begins with an overview of the development of conservation and restoration practises in Italy, France, and England, and subsequently analyses the Spanish and Alhambra-specific contexts. In addition to bringing together in a single document the evolution of the criteria applied to the conservation of monuments and buildings, this study has provided an opportunity to reaffirm their perennial importance in the discipline of heritage conservation. Furthermore, it has provided an opportunity to explore how the Palatine City reflects evolving philosophical paradigms, methodological practises, and their application to one of Spain’s most important architectural complexes, further emphasising the Alhambra’s unique position as a case study and a framework for advancing the scientific discourse on heritage preservation.

1. Introduction

There is a large body of documents relating to the conservation of historic buildings and monuments: letters, recommendations, and regulations that bear witness to the consolidation of criteria relating to their preservation. The evolution of the criteria within the discipline has been shaped by a series of conceptual, technical, and philosophical advancements. Accordingly, the state of scholarship and publications has evolved significantly over the last centuries, characterised by a gradual shift from a direct and often invasive interventionist perspective to a more holistic, preventive, and respectful approach to the authenticity of cultural assets.

The present article examines the evolving practises through the lens of the Alhambra Palatine City, a site that uniquely embodies the complexities of conservation ideologies across different periods and cultural contexts (Figure 1). Over the centuries, the Alhambra has undergone numerous transformations that reflect changing attitudes towards heritage preservation. From the construction of the fortifications in the 9th century by the Zirids, to the first repairs in the 13th century with the arrival of the Nasrids, along with the construction of the first great palaces in the 14th century and their adaptations and modifications according to the tastes of the successive sultans who lived there, until the Christian conquest at the end of the 15th century when new ideals were integrated, the preservation of the Palatine City has always been preceded by a complicated discourse, intrinsically linked to the development of concepts of heritage preservation that originated in Europe.

Considering that the first step towards a complete understanding and evaluation of a cultural heritage site is the recognition of the general context before its particularities, this document starts with an overview of the development of conservation and restoration practises in Italy, France, and England, and subsequently analyses the Spanish and Alhambra-specific contexts. By examining the sequence of events in chronological order, the dual focus of this study seeks to provide a comprehensive understanding of the significance of the Alhambra as both a recipient of European conservation ideologies and a framework for advancing the scientific discourse on heritage preservation.

Therefore, the main objective of this study is to provide a complete overview of the concepts, regulations, and criteria developed in Europe and their consequences in the Alhambra Palatine City. Through an exhaustive historical analysis, based on the most relevant bibliographical and documentary sources in the discipline of conservation and restoration of historic buildings and monuments, this study aims to highlight the importance and influence of these aspects in the methodologies applied to the interventions carried out in the Alhambra from its Christian period (1492) until the arrival of Leopoldo Torres Balbás (1923).

2. The Evolution of Conservation and Restoration in Europe: Contributions from Italy, France, and England

2.1. The Italian Case

Architectural knowledge of monuments was first addressed in the 1st century BC with the manuscript De Architectura. Known as Marcus Vitruvius’ Ten Books of Architecture, this writing not only called for historical knowledge of buildings by architects, but also included measures for their proper maintenance (Vitruvius Polion and Sanz 2019, pp. 69–71).

Meanwhile, after the Christianisation of the Roman Empire in the 4th century AD, the plundering of monuments considered pagan and the reuse of their materials for new constructions increased considerably, so that such practises soon gave way to widespread vandalism of ancient temples and public buildings (Arce Martínez 1975; Hanson 1978; Klein 1995; Saradi-Mendelovici 1990).

As a result, from the 5th century AD onwards, the first regulations and decrees aimed at preserving historical buildings appeared. The earliest initiatives emerged from a primarily pragmatic perspective. These include the orders of the emperors Leo I (401–474) and Majorian (457–461) in 458 AD, which formalised the non-destruction of temples and monuments, and the regulations of Theodoric the Great (454–526), whose concern for the preservation and respect of ancient buildings led him to appoint the figure of the “curator” to look after the sculptures and the “public architect” to inspect the monuments (Jokilehto 1986, p. 25).

Subsequently, during the 15th century, a series of protective measures emerged in the form of Papal Bulls, which, in this instance, were supported by an institutional backing and official character. Among the most important are: Etsi in cunctarum orbis, promulgated on 30 March 1425 by Pope Martin V (1368–1431), which established the office of Magistri viarum with the aim of maintaining and repairing buildings to a certain extent (McCahill 2013, p. 35); Cum almam nostram urbem in 1462 by Pope Pius II (1405–1464); and Cum Provida by Pope Sixtus IV (1414–1484) in 1474. The latter two were mainly addressed to buildings that were still in use and prohibited their destruction and plunder (Alegre Ávila 1994, pp. 49–50).

In light of the aforementioned facts, during the Renaissance, St. Peter’s Basilica in the Vatican exemplified the duality of conservation and restoration in a pragmatic sense. The original structure, erected by Constantine I (ca. 280–337), had undergone significant expansion and embellishment over a period exceeding a millennium. However, essential conservation work was largely neglected for several years. A commission established by Pope Gregory X (1210–1276) between 1271 and 1276 assessed the state of preservation of the Basilica. Subsequently, Pope Nicholas V (1397–1455) initiated the inaugural Renaissance renovation (McCahill 2013, p. 5).

Concurrently, the collecting trend, which originated in ancient Greece and was revived in the early Renaissance, enabled the sale of numerous works of art to private collectors in Rome (Jokilehto 1986, p. 7). Pope Paul II (1417–1471) initiated this tendency by building the Palace of Venice as a gallery to display his collection. Later, Pope Sixtus IV sold part of this collection to the Medici and donated the rest to the Palazzo dei Conservatori on the Capitoline Hill, allowing the opening of the first public museum, the Capitoline Museum, in 1471. These early collections displayed statues that were generally mutilated, i.e., in their original state. This was the case of the Torso of Belvedere and the Laocoon, which were exhibited in the Villa of Belvedere, built by Donato Bramante (ca. 1444–1514) at the request of Pope Julius II (1443–1513) (Jokilehto 1986, pp. 34–36). At the same time, Donatello (ca. 1386–1466) began the restoration of sculptures and architectural fragments in the Medici palace in Florence (Conti 2003, p. 32). Both practises have given rise to the great debate between conservation and its opposite, restoration. The most emblematic examples of both practises are seen most clearly in the Torso of Belvedere, in terms of conservation, as it has maintained its original state to the present day, and the Laocoon, in terms of restoration, as it began a long journey (from 1520 to 1960) towards its reintegration, passing through several interventions focused mainly on the position of one of its arms (Pirazzoli 1994, pp. 29–34; Conti 2003, pp. 33–37).

In the 16th century, a report by Raphael Sanzio (1483–1520) to Pope Leo X (1475–1521) is recorded after he was appointed “Inspector of the Marbles and Stones of Rome” by the pontiff. It was edited by Iacopus Mazochius and published in 1521 as Epigrammata antiquae Urbis (Jokilehto 1986, p. 39). In this text, Raphael describes with dismay the destruction of ancient monuments.

≪Quanti pontefici, padre santo quali avevano el medesimo officio che ha Vostra Santità, ma non già il medesimo sapere, né il medesimo valore e grandezza d’animo, quanti -dico -pontefici hanno permesso le ruine e disfacimenti delli templi antichi, delle statue, delli archi e altri edifici, gloria delli lor fondatori! Quanti hanno comportato che, solamente per pigliare terra pozzolana, si siano scavati i fondamenti, onde in poco tempo poi li edifici sono venuti a terra! Quanta calcina si è fatta di statue e d’altri ornamenti antichi! [How many pontiffs, Holy Father, who had the same office as Your Holiness, but not the same knowledge, nor the same courage and greatness of spirit, how many—I say—pontiffs have allowed the ruin and destruction of ancient temples, statues, arches and other buildings, the glory of their founders! How many have caused the foundations to be dug only to receive pozzolanic soil, so that in a short time the buildings have collapsed! How much limestone was used for statues and other ancient decorations!]≫.

The reconstruction of a public building for religious purposes was one of the alternatives presented in this century. An example of this is the Church of Santa Maria Degli Angeli, built on the “tepidarium” of the Baths of Diocletian (Pirazzoli 1994, pp. 77–82). Among the reconstruction projects presented at the time, Michelangelo Buonarroti (1475–1564) stood out, basing his proposal on the idea that additions should only be accepted if they were necessary for the stability or significance of the work, and the idea of minimal intervention, which anticipated the contemporary concept of both principles by several centuries (Jokilehto 1986, pp. 43–45).

In the 18th century, architectural restoration was characterised by the reconfiguration of buildings in the decorative style of the Baroque through the use of “pasticci”, i.e., the assembly of different types of fragments of different provenance and quality. This method influenced what is known today as material reintegration, especially in the decoration of monuments and façades (Pirazzoli 1994, p. 28; Conti 2003, p. 103).

As regards the frescoes, the interventions of Carlo Maratta (1625–1713) are particularly noteworthy, since Maratta opposed the restorationist attitude of the time. To cover the décolleté of Guido Reni’s Madonna Che Cuce, he carefully painted the required veil with reversible materials so that it could be restored to its original state if necessary. In the restoration of the Palazzo Farnese Gallery in Rome, Maratta intervened with an interdisciplinary methodology based on methods of conservation, consolidation, and pictorial reintegration using watercolour retouching. In general, Maratta offered an authentic and systematic programme of intervention, giving priority to conservation and anticipating the criterion of the reversibility of materials (Carbonara 1997, p. 58; Conti 2003, pp. 107–18).

The 18th century was accompanied by fundamental cultural, scientific, and technological changes. The French Revolution, the Enlightenment, and the generalisation of publications and treatises on art and architecture directly enabled the emergence of disciplines such as Art History, Aesthetics, and Archaeology (Jokilehto 1986, pp. 6–9). This environment of development, together with the experience already acquired in the field of heritage and its interventions, was responsible for laying the foundations for the scientific treatment of cultural heritage in the following centuries. It was at this point that, in the context of classicism and rationalism, the debate began, for example, between the opposing concepts of conservation and restoration, as well as the role of the restorer in relation to the need for a correct historical artistic evaluation of works of art and monuments. These facts favoured, on the one hand, the gradual professionalisation of the discipline of restoration and, on the other, the appreciation of concepts such as minimo intervento, manutenzione and prevenzione (Carbonara 1997, p. 59).

Among the most important contributions of the 18th century that directly influenced the development of conservation theory were the studies of Johann Winckelmann and the drawings and engravings of Giambattista Piranesi.

Johann Joachim Winckelmann (1717–1768) is regarded as the most important connoisseur of classical antiquity and the father of Art History and Archaeology (Tantillo 2010, p. 3). In his studies as Superintendent of Antiquities in Rome and Antiquarian of the Apostolic Chamber, and through his works Reflections on the Imitation of the Greeks in Painting and Sculpture of 1755 and History of the Art of Antiquity of 1764, he established comparative methodologies, giving priority to primary sources (monuments), distinguishing between originals, additions, and copies, focusing his attention on the conservation of the original, and documenting all his interventions in various publications (Carbonara 1997, pp. 71–73; Winckelmann and Chamorro Mielke 2011; Winckelmann and Mas 2007). Winckelmann developed the modern principles of conservation and initiated the first steps towards the use of a scientific method based on the analysis, description, identification, and documentation of monuments. This methodology was reflected in the unprecedented systematisation and detailing of the archaeological excavations of Pompeii and Herculaneum after their discovery (Carbonara 1997, pp. 62–63; Jokilehto 1986, pp. 85–86). His contributions had a direct influence on restoration policies in Rome during the 18th and especially the 19th centuries (Pirazzoli 1994, pp. 92–96).

With the birth of Aesthetics, the contemporary autonomy of critical judgement, the basis for any intervention in historic buildings was introduced. Aesthetic theories around the categories of the picturesque and the sublime would be particularly influential in the development of conservation theory (Jokilehto 1986, p. 82). Initially applied to classical Italian and English landscape painting, these theories later enabled the qualification of ancient architecture in its environment, motivated the protection of the whole landscape, and promoted new criteria for the evaluation of heritage associated with ruins (Pirazzoli 1994, pp. 89–92). Associated with the poetics of ruins was Giambattista Piranesi (1720–1778), an architect by profession, although he devoted himself to drawings and engravings of Rome. In his studies, he analysed monuments like Vitruvius, not only considering the building itself, but also including measurements, historical, literary, and testimonial sources, anticipating the historiographical studies that emerged in the 19th century (Tantillo 2010, p. 8; Piranesi 1756).

Both artistic and archaeological assessments led to the protection of the first cultural assets between the end of the 18th and the beginning of the 19th century. This influence, moreover, quickly reached Europe, which regained interest in collecting, restoration, and, as a novelty, documentary tourism on the Grand Tour, leading to the first rigorous representations of historical monuments (Casiello 2008, pp. 58–60; Petrarca and Dotti 1978).

During the 19th century, the papal administration and the protection of antiquities, many of which had been plundered by the French until the withdrawal of Napoleon’s troops from Italy in 1799, were restored. During these years, the Apostolic Chamber had two departments with specific responsibilities for the protection of cultural heritage; the first, called Camarlengato, was responsible for, among other things, legislation, inspection and evaluation of antiquities, and the second, called Tesoro, was responsible for the financial aspects as well as the execution of works, excavations, and the restoration and maintenance of ancient monuments (Jokilehto 1986, pp. 123–24).

Among the most important edicts of the 19th century are the Papal Chirograph of 1802, signed by Cardinal Antonio Doria Pamphilj (1749–1821), together with its revision of 1820, signed by Cardinal Bartolomeo Pacca (1756–1844), which established a Technical Commission of Fine Arts for the protection of archaeological heritage, prohibiting the destruction of finds and including instructions for their conservation, and the compilation of the regulations Cum almam nostram urbem and Cum Provida, issued by the Commissioner of Antiquities Carlo Fea (1823–1896) between the same years.

However, it was not until the period between 1822 and 1839 that the legal framework for the protection of Italy’s historical and artistic heritage was established. During this period, the Law VII of Charles of Borbone established the Commission of Antiquities and Fine Arts, which was tasked with providing advice on the export of works of art. Furthermore, the edict instructed the administrative authorities to be vigilant in order to ensure that ancient works of art were not distorted by modern ones. Afterwards, following the unification of Italy, the Director General of Antiquities and Fine Arts, Giuseppe Fiorelli (1823–1896), drafted an important circular (1882) in which he called on the technical expertise of prefects and former presidents of the Commissions for the Preservation of Monuments in order to avoid both questionable interpretations and errors in restorations (Casiello 2005, pp. 70–75).

2.2. The Case of France

France was responsible for the creation of the first institutions for the defence of historical heritage and also for the development of new concepts linked to the basic principles of conservation and restoration of heritage in general, which are still in force today. It adopted an empirical model, the forerunner of stylistic restoration, which would later distance itself from the model of modern conservation and scientific intervention developed in Italy through archaeological restoration and art historical studies.

At the end of the 17th century, the first publications on the cataloguing and inventory of monuments appeared in France. These included Mémoires pour servir à l’histoire des Maisons royales by André Félibien (1619–1695) in 1681 and Les Monuments de la Monarchie française by Bernard de Montfaucon (1655–1741), published between 1729 and 1733 (Quirosa García 2008, p. 14). Two centuries later, at the beginning of the 19th century, Ludovic Vitet (1802–1873) produced a more systematic and detailed inventory of monuments. Vitet, inspecteur général des monuments historiques and president of the Commission des Monuments Historiques, was responsible for the cataloguing and analytical documentation of France’s monuments. He also carried out an extensive programme of conservation of French monuments, including historical and archaeological information, and contributed to the important documentary legacy of the Archive des Monuments Historiques (Carbonara 1997, pp. 104–105).

The French Revolution was a key moment in the development of protection policies. It marked the beginning of an era of looting and destruction of works of art and historic buildings in France, encouraged in part by the suppression of monasteries and the dispossession of wealthy families. Faced with this deliberate destruction and vandalism, the National Assembly decreed in 1790 the creation of the first Commission des Monuments, which at that time had various specialists to assess issues related to historic artistic heritage. Similarly, on 14 October 1791, the creation of the Comité d’Instruction Publique, whose main task would be the preservation of monuments, was announced, and in 1793 a new Commission des Arts, later called the Commission Temporaire des Arts, was also created (Jokilehto 1986, p. 115).

The first conservation rules approved by decree in France date from August 1792, but between 1793 and 1794 the National Assembly promoted the drafting of an important Instruction sur la manière d’inventorier et de conserver dans toute l’étendue de la République tous les objets qui peuvent servire ux arts, aux sciences et à l’enseignement. This instruction is considered to be the beginning of legal action in favour of historical heritage, as it contains measures for the conservation of important objects of art and science (Quirosa García 2008, p. 14). In 1794, Abbe Henri Grégoire (1750–1831), Bishop of Blois and member of the Comité d’Instruction, published reports on how to avoid destruction and vandalism, as well as a study on the educational reasons for preserving cultural heritage (Rücker 1913, p. 94; Jokilehto 1986, p. 116).

During the 19th century, many people contributed to the development of conservation theory. Among them were François-René de Chateaubriand (1768–1848), who introduced History into literary publications such as Le Génie du Christianisme (1802) and Les Martyrs (1809); Victor Hugo (1802–1885), a key figure in the fight against vandalism, who published two editions of Guèrre aux Demolisseurs (1825 and 1832) and the popular Notre-Dame de Paris (1831); the Inspecteur général des monuments Prosper Mérimée (1803–1870), who published several research reports on French monuments, such as Notes d’un voyage dans le midi de la France in 1835, Notes d’un voyage dans l’Ouest de la France in 1836, l’Auvergne et le Limousin in 1838, and la Corse in 1840; Arcisse de Caumont (1802–1873), author of the Essai sur l’architecture religieuse du moyen âge in 1824 and the Cours d’antiquités monumentales in 1830, which led to the creation of the Société française d’archéologie in 1834; and finally, Eugène Viollet-le-Duc (1814–1879), architect, archaeologist, historian, and the person most responsible for the introduction of stylistic restoration in France (Arrêté ministériel du 29 Septembre 1837 Instituant une Commission des Monuments Historiques. Paris: Ministry of the Interior, vol. II, 1837, pp. 57, 132, 212, 352, 392, Appendix A).

Contrary to the tendency towards minimal intervention and strict conservation influenced by archaeological restoration in Italy, Viollet-le-Duc was responsible for reviving the debate between conservation and restoration in France. As a systematiser and compiler, he created the first vertebral corpus on restoration as a modern discipline and gave content to the concept of “repristino” in accordance with nationalism, Christianity, and the art historical consciousness of his time (Martínez Yáñez 2006, pp. 77–79). His theory was reflected in numerous publications and restoration reports, including The Dictionnaire raisonné de l’architecture française du XI au XVI siècle, produced in ten volumes between 1854 and 1868, in which he provides the first definition of restoration; Entretiens sur l’architecture of 1863–1872, produced in three volumes; Histoire d’une forteresse of 1874; La Decoration appliquée aux édifices of 1893; and many others. Among his most important interventions were those on the Church of Sainte Madeleine de Vézelay (1840–1859), the Cathedral of Notre Dame (c. 1843–1868), the Citadel of Carcassonne (1846–1879), and the Château de Pierrefonds (1858–1870).

2.3. The Case of England

In England, parallel to what was happening in France, there was an eagerness to revive the Gothic, but with completely opposite motives and results. In this case, it would be the first anti-restoration movement with an international and universal projection. While in Italy in the 18th century there was a passion and defence of ruins, and in France the recovery of medieval styles was gaining strength, in England the same reasons were combined to promote the creation of the first societies for the protection of the medieval heritage.

In 1811, the National Society for the Education of the Poor in the Principles of the Established Church was founded with the aim of strengthening the Church in the face of the disturbances caused by the French Revolution. Augustus Welby Northmore Pugin (1812–1852) was the initiator of the Neo-Gothic movement. He regarded the restoration of medieval monuments as a religious event and, according to his theory, the first phase of restoration corresponded to the “restoration of ancient feelings and sentiments” (Jokilehto 1986, pp. 292–95). His influence inspired the creation of the Cambridge Candem Society, founded by John Mason Neale (1818–1869) and Benjamin Webb (1819–1885), the creation of the journal The Ecclesiologist, whose aim was to promote conscientious and specialised restoration, and the founding of a society in Oxford for the study of Gothic architecture, later called the Oxford Architectural and Historical Society (White 1962, pp. 25–44).

After this period, the criticism of stylistic restoration expanded, and conservationist thought was consolidated. John Ruskin (1819–1900) and William Morris (1834–1896) were the two most important figures in the anti-restoration movement in England. Ruskin is regarded as the first proponent of strict conservation and maintenance as the only possible models of protection. Although he did not write a theory of conservation per se, the influence of his writings and speeches spread worldwide led to the rejection of stylistic restoration in an increasing number of countries (Carbonara 1997, pp. 161–171). Among his most important works are Modern Painters, written in five volumes between 1843 and 1860, The Stones of Venice, written in three volumes from 1851–1853, and The Seven Lamps of Architecture, written in 1849. All reflected an unprecedented clarification of the values that characterised the architectural heritage (Landow 1971, pp. 22–25, 82–84). Ruskin, also regarded as the founder of modern theory, defended the authenticity of material and the existence of monuments in themselves, anticipating the concept of preventive conservation that emerged in the twentieth century (Ruskin 1857, pp. 162–63). His writings also encouraged the appreciation of ruins, as did Piranesi’s, by defending the relationship between them and their surroundings, a crucial factor in the protection of the landscape and the environment in general.

William Morris, for his part, became a fundamental figure in Art History and Conservation, even more influential than his predecessor in the anti-restoration movement. He was the founder of the Arts and Crafts movement of the Society for the Protection of Ancient Buildings (SPAB) and author of its manifesto in 1877. The importance of this manifesto would be decisive in the unification against the arbitrariness of restoration, in the dissemination of conservation as the main criterion for intervention and in the universal defence of conservative ideas (Carbonara 1997, pp. 165–70). This manifesto, which became the theoretical basis of modern conservation policy, stipulated that protection should never be limited to specific artistic styles or monuments, but should be based on a critical evaluation of the values of the entire heritage. It also added that buildings should always be preserved in situ, with special attention to their daily maintenance, taking into account the urban and natural environment of monuments and ruins, and emphasised the incipient appreciation of the historic city (Carbonara 1997, p. 171; Pirazzoli 1994, pp. 146–49). Morris’s vision led to the extension of heritage protection to the rest of Europe and Asia through the creation of the Foreign Committee, an organisation that would defend the universal values of heritage, cultural diversity in its tangible and intangible aspects, and would mark the path for heritage protection in the 20th century.

3. Guidelines and Regulations in the 20th Century

3.1. New Directions

The 20th century was marked, on the one hand, by the emergence of new models of intervention and the creation of specialised institutions and, on the other hand, by the publication of international regulations and laws governing the conservation, restoration and protection of cultural heritage. The models of intervention that echoed throughout the century were: the “Restauro Filologico” of Camilo Boito (1836–1914), the “Restauro Storico” of Luca Beltrami (1854–1933), the theory of Alöis Riegl (1858–1905), the “Restauro Scientifico” of Gustavo Giovannoni (1873–1947), and the “Restauro Critico” of Cesare Brandi (1906–1988).

Boito’s philological restoration, seen as an anticipation of scientific restoration which understood buildings as historical documents, shared with Ruskin the need to maintain and preserve, respecting the principle of minimum action, and allowed aesthetic restorations as a final means of consolidation, always distinguishing between the old and the new. This model opened the door to the later concept of technical and material differentiation of additions, the technification of Restoration, and constituted the first Charter of Restoration after its presentation at the IV Congress of Architects and Civil Engineers in Rome in 1883 (Carbonara 1997, pp. 202–205).

Beltrami’s historical restoration was based on a rigorous knowledge and documentation of the buildings, anticipating the “case-by-case” approach still used today. However, as in the case of stylistic restoration, its main objective was reconstruction. The best example of this model can be found in the “com’era e dov’era” intervention of the Campanile di San Marco in Venice (Jokilehto 1986, pp. 345–46).

Riegl, in turn, established the democratisation and universality of the concept of heritage, whose global foundation, maintained by Ruskin, Morris, and the SPAB, would lead to the emergence of the international doctrine of historical heritage. Riegl developed a system of global protection that included both aspects relating to the criteria for intervention and others relating to the legislation and management of monuments. His theory was the basis for the discipline of Heritage Conservation, and in terms of criteria he distinguished between the value of memory (historical and antique) and the contemporary value of buildings. From the historical point of view, he derived the need to preserve the buildings and additions of all historical periods, and from the contemporary point of view he derived the need to preserve the public, democratic, and universal value and the subjective basis of the buildings, the pillars of heritage conservation in practice today (Jokilehto 1986, pp. 378–80).

Giovannoni’s scientific restoration was based on the preservation of the documentary character of the monument, as well as on the historical and technical knowledge of the professional restorer (Giovannoni 1925, 1931; Giovannoni and Ventura 1995). It was the dominant model in the first half of the 20th century, represented by figures such as Leopoldo Torres Balbás and Jerónimo Martorell in Spain, Gino Chierici and Ambrosio Annoni in Italy, Paul Leon in France, and Nicholas Balanos in Greece. In addition to reaffirming the basic principles added by Riegl (relativity, individuality and subjectivity), Giovannoni rejected mimetic additions and defined the so-called “integrity of monuments” by taking into account their environment and context. This model is of great importance due to its internationalisation and incorporation into the heritage laws of the time through the Athens Charter of 1931.

Cesare Brandi’s critical restoration was the most important model in the second half of the 20th century, although in this case it focused mainly on movable objects. This model is particularly notable for its work on the recomposition of murals and the specific training of restorers. The principles of this model were set out in the Teoria del Restauro of 1964, translated into Spanish in 1988, and in the Carta del Restauro of 1972, which Brandi himself promoted internationally (Carbonara 1997, pp. 303–308).

As far as regulations and institutions are concerned, the Athens Charter of 1931, which contains the conclusions of the International Conference of Experts for the Protection and Conservation of Art and Historical Monuments, stands out. Its symbolic value is justified by the fact that it was the first document promulgated by an international heritage body to refer specifically to the criteria (principles) of intervention in historic monuments. Its most important contributions include the general acceptance of the criteria presented, the defence of monuments for the whole of humanity, and the international cooperation in favour of their conservation (Trachana 1998).

Also noteworthy are The Italian Charter of Restoration of 1932, the creation of the United Nations Educational, Scientific and Cultural Organisation (UNESCO) in London in 1945, the creation of the International Institute for Conservation (IIC) in 1950, the Hague Convention of 1954, the creation of the International Centre for the Study of the Preservation and Restoration of Cultural Property (ICCROM) in 1956, the Venice Charter of 1964, the creation of the International Council on Monuments and Sites (ICOMOS) in 1965, the 1972 World Heritage Convention and the 1977 Guidelines and Practices for its Implementation which established the first World Heritage List, the 1975 European Charter on Architectural Heritage and the Amsterdam Declaration, the 1985 Convention for the Safeguarding of the Architectural Heritage of Europe, the 1994 Nara Document on Authenticity, and finally, the 2000 Krakow Charter.

3.2. The Spanish Regulatory Evolution

The origins of the legal concern for the conservation and protection of historical heritage in Spain can be ascribed to the Italian experience and international influence. They have provided foundational principles and practises that Spain has gradually adapted to its unique historical and cultural context through royal decrees, institutional frameworks, and restoration criteria. The first Spanish regulations appeared under the auspices of the Academies of History and Fine Arts of San Fernando in the mid-18th century, a period in which the Bourbons began to dictate a series of regulations for the care and conservation of antiquities, historical monuments, and works of art. At the beginning of the 19th century, concern for the protection of monuments was expressed in the 3rd Law of the Novísima Recopilación, the Instruction of 1802, and the Royal Decree of 1803, which for the first time defined the so-called “ancient monuments”, together with some measures for their protection (Alegre Ávila 1994, pp. 41–42).

In the first quarter of the 20th century, the Law of Excavations and Antiquities of 1911 and the Law of Monuments of 1915 were passed, which included measures for the conservation of monuments (Barranco Vela et al. 2009, p. 112). This was followed by the Royal Decree-Law of 15 August 1926, which contained provisions that were quite up-to-date. These included the prohibition of demolition, the inclusion of express ministerial authorisation in exceptional cases, and the imposition of the duty of conservation on private owners under penalty of expropriation (Royal Decree-Law on the National Archaeological Artistic Treasure, n. 227 of 15 August 1926, articles 8 and 12, Appendix A).

The introduction of specific criteria for intervention came with the law of 1933, which, influenced by the Athens Charter of 1931, prohibited the reconstruction of monuments and added the presentation of a project prior to any intervention (Law of 13 May 1933 on the National Artistic Heritage, n. 145 of 25 May 1933, articles 19 and 23, Appendix A). However, the Law 16/1985 on Historical Heritage (LPHE) is the most important law in Spain. Its provisions, which are still in force, incorporate the principles of minimum intervention, giving priority to the conservation, consolidation, and maintenance of monuments, and even providing for rehabilitation. This law also includes the obligation to respect existing additions from all periods and imposes the principle of discernment with respect to the originals, in order to avoid distortion or imitation contrary to the authenticity of the monuments (Law 16/1985 on the Spanish Historical Heritage, n. 155, of 29 June 1985, article 39, paragraphs 1 to 4, Appendix A).

However, in order to understand the treatment and criteria for conservation in Spain, it is necessary to refer to the autonomous law, since the Spanish Constitution includes and recognises specific competences that are embodied in the autonomous laws for the protection of the architectural heritage of the different Spanish territories (Barranco Vela et al. 2009, pp. 66–68, 115). The Law on the Historical Heritage of Andalusia (LPHA), for example, provides a material classification of heritage typologies within the level of protection of Cultural Heritage (BIC), distinguishing, among others, between the categories of monument, ensemble, garden, and historic site (Law 14/2007 on the Historical Heritage of Andalusia, Appendix A).

With regard to the specific case of the Alhambra and the Generalife, it is also worth mentioning some peculiarities that affect both its regulatory environment and that of its conservation and protection. The Alhambra belonged to the Crown from the time of the Christian conquest in 1492 until shortly after the Revolution of 1868. In October 1868, this monumental complex became part of the artistic heritage of the State, which entrusted its custody and conservation to the Granada Provincial Monuments Commission by declaring it a National Monument in 1870 (Dias Martins 2024, p. 108).

At the beginning of the 20th century, an administrative system was consolidated and led to the creation of specialised agencies for the protection of the monument. Initially, the care of the Alhambra was entrusted to the Special Commission of 1905, which was replaced in 1913 by the Patronato de Amigos (Council of Trustees). Later, in 1915, the latter came under the authority of the General Directorate of Fine Arts. In 1917, the General Plan for the Conservation of the Alhambra was drawn up and in 1921 the Generalife was assigned to the Spanish State. In 1940, by Royal Decree of 9th March, the Ministry of National Education created the Patronato de la Alhambra y Generalife, with the aim of creating a residence and museum in the Palace of Charles V (Dias Martins 2024, p. 108).

Later, in 1944, a new Council of Trustees was created, which remained in place until the cultural functions and services of the State were transferred to the Autonomous Community of Andalusia. In 1984, the Palatine City was declared a World Heritage Site by UNESCO, and in 1986, the Special Plan for the Alhambra and the Alijares and the Statutes of the Patronato de la Alhambra y Generalife, the body currently responsible for the management, conservation, and protection of the Alhambra and the Generalife, were approved. Finally, on 23 March 2004, the complex was declared a Cultural Interest Asset (BOE no. 127, 26 May 2004, Appendix A), which changed its previous category of Historic Artistic Site to the more appropriate category of Monument, thus providing a protective environment that is appropriate to the characteristics of this monumental complex (Villafranca Jiménez 2007, p. 4).

4. The Conservation of the Alhambra and Generalife Palatine City

In the last years of its existence, the Nasrid Emirate was caught up in a prolonged series of dynastic conflicts and fratricidal struggles, which, in addition to the war against the Christian threat, caused serious damage and destruction to the palaces (Vilar Sánchez 2007, pp. 30–31). However, two documentary references from this period suggest that the Catholic Monarchs had already foreseen the state of conservation of the palaces at that time. The first is found in one of the clauses of the Capitulaciones of 25 November 1491, which reads as follows ≪que los rehenes fijados quedarían en poder de sus altesas, los Reyes Católicos, por término de dies días, en tanto que las distintas fortalesas del alhambra e alhiçan se reparan y proueen e fortalecen [that the fixed hostages would remain in the power of their highnesses, the Catholic Monarchs, for a term of ten days, while the different fortresses of the alhambra are repaired and fortified and strengthened]≫. The second record is contained in the Royal Decree of the Sovereign of 12 February 1492, addressed to the Council of Seville, which confirmed these suspicions and stated that it had agreed to the licencing and dismissal of most of the people who had left Granada for the Conquest ≪quedando alguna poca della para la guarda, lauores o rreparos que en el alhambra e en la cibdad mandamos fazer, que son tan necesarios que non se pueden escusar [There is still a little left over for the guarding, work and repairs that we ordered to be carried out in the alhambra and in the city, which are so necessary that they cannot be excused]≫ (Torres Balbás 1951, p. 192).

After the Conquest, when the Palatine City became part of the Crown’s patrimony, large sums of money were spent on repairs and works of great importance. One of the first concerns of the Christian monarchs was the urban planning of the city. The clear distinction between Muslim and Christian life and society required far-reaching changes. Between the desire for change and the difficulty of creating a new city, the solution found by the monarchs was to adapt the old to the new, a kind of cultural symbiosis that allowed the construction of new buildings on the outer limits of the wall and the reuse of public spaces, mosques, necropolises, and palace rooms (Díez Jorge et al. 2018).

In the palace rooms, most of the work consisted of adapting the palaces, both in terms of conservation and maintenance tasks, as well as restoration work (Vilar Sánchez 2007, pp. 42–43). In this first stage, most of the conservation and maintenance works were urgent, and most of them focused on the conservation of the roofs (Gómez Galisteo 2023, p. 106). An example of this is the hiring of Master Abrahán de las Maderas, a Mudejar specialist who was responsible for the carpentry work carried out in the Casas Reales from 1492 onwards, and who carried out ≪great works in the Arabic style with mastery and skill≫ (Casares López 2008, p. 297). One of his most notable works was the replacement of several dilapidated beams that supported the “ceiling-floor” planks in both the lower rooms and the upper floors of the “Quarto de los Leones”.

As far as restoration is concerned, the most obvious example of restoration is the work carried out on the Alhambra’s architectural ceramics, especially its tiles (azulejos) and tiling mosaic pieces (alicatados) (see Figure 2, Figure 3 and Figure 4), some of which are still preserved in the collections of the Alhambra Museum (Dias Martins 2024, pp. 107–11). It should be remembered that the palaces and the various Nasrid rooms were covered, both inside and outside, with tiles that had an aesthetic and ornamental purpose. There are three main documents that reflect and testify to this work. The first is the receipt for the services of the “Moor” Maomet, master tiler, for the laying of 1020 tiles in the Royal House (AGS, Legajo 140 del 11 de marzo de 1492, p. 124, Appendix A). The next account is based on the transcriptions of one of the first travellers to visit the Alhambra, the Austrian-German Hieronymus Münzer (1437–1508), who at the end of October 1494 recorded the ≪aesthetic transformations that were being carried out in the Generalife at the time and that gave the monument an impressive beauty≫ (Vilar Sánchez 2007, p. 70). The third document is a letter from the Queen, dated 18 July 1500, in which she orders the payment of 1500 maravedíes to Diego de Vadillo ≪for bringing nine acémilas loaded with tiles from the city of Seville to Granada≫ (Torres Balbás 1951, p. 194).

In the 16th century, the first restoration work is documented in the palace of the former convent of San Francisco de la Alhambra, founded in one of the first Nasrid palaces, known as the Palace of the Infantes, which was renovated to house the residence of the Christian kings and where the remains of Queen Isabel were later buried until the construction of the Royal Chapel (Orihuela Uzal 1996, pp. 78–80).

It is also worth noting that the reuse of materials was a common practice during this period in the Alhambra, with tombstones being a particular example. Two documents are relevant here: the Royal Decree of 20 September 1500, which ordered the closure of all cemeteries in Granada, and the Royal Decree of 15 October 1501, which established the Regulations of Granada and permitted the reuse of Moorish tombstones and ossuaries in the construction of civil and religious buildings in Granada. Many buildings in Granada benefited from these donations, including the Alhambra. The most notable example can be seen in the wall attached to the Gate of Justice (Figure 5), which uses several tombstones as ashlars (Vílchez Vílchez 1984, p. 252; 1986, p. 93; Gómez-Moreno González 1888, p. 242).

The 17th century reveals an important activity related to the purchase of glazed architectural ceramic pieces and the contracting of specialised services for their installation (Vilar Sánchez 2013). The occasional replacement of pieces used in the 16th century could have become a restoration criterion in different areas of the Alhambra in the 17th century. These replacements could have come from the purchase of new pieces in major production centres such as Seville, or from the reuse of Nasrid pieces from other parts of the Alhambra (Gómez-Moreno Calera 2005, pp. 7–28).

The century between the mid-18th and 19th centuries, which also coincided with the Enlightenment and Romanticism, was the most disastrous for the state of conservation of the Alhambra, firstly because of its total abandonment and secondly because of the inappropriate use of its spaces. Among these events, the following stand out: the installation of industries in the Nasrid palaces, the indiscriminate occupation of the enclosure that included several private dwellings (Figure 6), the state of ruin of many rooms, their use as military base for the French troops during the Napoleonic occupation, the Liberal Revolution with its respective wars, disentailments and scarce economic resources, and finally the constant looting and plundering by the local population and even by some accountants and governors of the Palatine City (Barrios Rozúa 2016; 2011, pp. 231–75).

This period also saw the most significant changes in the criteria for intervention in the Palatine City. The wide-ranging debate that was already raging in Europe about conservation and restoration as mutually exclusive options was to continue in the Alhambra until the early decades of the 20th century. Specifically, the monumental complex went from the picturesque and sublime appreciation that was emerging in Italy at the same time, to the restauraciones adornistas (ornamental restorations) carried out by the Contreras family (1824–1906), then to the archaeological restoration under the direction of Ricardo Velázquez Bosco (1843–1923), and finally to the scientific restoration under Leopoldo Torres Balbás (1888–1960).

Meanwhile, since the end of the 18th century, historical interest and the study of material remains have played a pivotal role in the reappraisal of Hispano-Arab architecture. It is worth mentioning the significant impact of the Grand Tour, whose travellers, in addition to exerting pressure on the relevant authorities to adopt appropriate methods of intervention, made a substantial documentary contribution through their detailed descriptions of the state of conservation of the Palatine City, both before and after the interventions. The traveller Richard Ford (1796–1858), for example, denounced the looting of the Alhambra. According to his words ≪Don Jose Prado, the Contador, and Antonio Maria Prieto y Venencio, the Escribano have gutted the Alhambra, they tore off door-locks and bolts, took out even panes of glass, and sold everything for themselves≫ (Ford 1845, p. 382). A letter written by Washington Irving (1783–1859) in 1829 tells of a group of Italian artists working in some of the outbuildings to repair the Alhambra. Months later, Carolin W. Cushing (1802–1832) pointed out that these rooms were above the baths and refers to the Italian firm as being responsible for restoring the Alhambra to as much of its original appearance as possible (Wilde Cushing 1832, pp. 309–10).

In the mid-19th century, Girault de Pranguey (1804–1892) carried out an analysis of the architectural, chromatic, and ornamental components of the Alhambra, which was later published in his Plans, elevations, sections and details of the Alhambra, published in London in 1842 and in Paris in 1845, with 101 engravings. In 1850, Francisco Pi y Margall (1824–1901), from a more contemporary point of view, described how the restoration of the Alhambra had become a burning issue in the middle decades of the 19th century. In 1856, Owen Jones (1809–1874), in The Grammar of Ornament, one of the most influential writings on architecture in the second half of the 19th century, was responsible for finally establishing the universal role of the Alhambra’s aesthetic system (Figure 7) in defining the ornamental principles of modern architecture (Calatrava 2008, p. 85).

Later, the interest in changing the image of the Alhambra as a ruin and in disproving the idea of a backward Spain in European eyes contributed to the emergence of regulations aimed at protecting and safeguarding the Palatine City. Examples of this are the Law of 18 December 1869, which established the alienation of the assets of the Royal Heritage, and the Order of 12 July 1870, based on a report by the Provincial Monuments Commission of Granada, which placed the Alhambra under its direct control and supervision by declaring it a National Monument (Dias Martins 2024, p. 108).

It is worth mentioning that the same romantic framework that captivated European travellers during the Grand Tour also inspired the ornamental restorations carried out in the City. This period introduced an orientalist perception, which idealised Spain as the symbol of exoticism and alterity. Thus, the Alhambra, with its Nasrid architecture and evocative historical legacy, epitomised this fascination, consequently cementing its place in the artistic and literary imagination of the Romantic travellers and serving as a tangible link to justify the intention of recovering its “original Islamic splendour” through these interventions.

Among the ornamental restorations, whose intervention criteria were maintained during the last three quarters of the 19th century, some very aggressive and controversial ones stand out. The first of these was the transfer of the doors of the Hall of the Abencerrajes (Figure 8) to the southern gallery of the Court of the Myrtles. This was carried out in 1837 by Governor Juan Parejo and involved the cutting of the doors to adapt them to their new location. The next intervention, this time carried out by the architect José Contreras (1794–1874) in 1842, involved the complete scraping of the columns of the Court of the Lions (see Figure 9 and Figure 10) in order to clean them, causing them to lose part of their shape, polychromy and, above all, their patina. A year later, José Contreras carried out the partial demolition of the Sala de las Camas del Baño Real del Palacio de Comares (Royal Baths of Comares Palace) (Figure 11) in order to rebuild it, an extensive work that, due to lack of funds, was not completed until 1849 by his son, Rafael Contreras (1826–1890) (Barrios Rozúa 2016, pp. 63–64, 93–94, 143–49).

Finally, between 1915 and 1917, the architect Ricardo Velázquez Bosco, a pioneer in the field of conservation, drew up the General Conservation Plan for the Alhambra, which reflected his archaeological and conservation concerns (Villafranca Jiménez 1998, p. 242). His critical attitude towards stylistic restoration would be translated into a commitment to what is known as philological restoration, which took into account the specific history of the monument, knew the vicissitudes of its existential journey through archaeological, graphic and written documentation, focused on the places most affected by ruin and abandonment, and always opted for projects aimed at the consolidation, archaeological excavation, maintenance, and organisation of the Palatine City. Velázquez Bosco laid the foundations for a new phase of intervention in the Alhambra, which, after 1923, fell to Leopoldo Torres Balbás, the main person responsible for implementing the most up-to-date conservation policy, based on scientific criteria, in the Alhambra and the Generalife Palatine City. Torres Balbás’ initial and most significant contributions were the consolidation, repair, and maintenance of the Tower of the Comares Palace, the mosque of the Partal, the gardens, orchards, and water reservoirs of the Alhambra, and the Palace of the Convent of San Francisco. Additionally, he completed the construction of the Palace of Charles V, concluded the consolidation of the Tower of the Queen’s Robing Room, and initiated the restoration of the roofs of the pavilions of the Court of the Lions, as he himself described in an interview with a Madrid newspaper in February 1933 (see Figure 12).

5. Results

5.1. General Premises

This research allows us to consider the manuscript “The Ten Books of Architecture” as one of the fundamental texts in the development of the understanding of the architectural object as a historical, artistic, and cultural document. Although it does not explicitly address the conservation of historic buildings, this manuscript has influenced the development of standards, criteria, and methodologies for the protection and conservation of historic architecture. Furthermore, it established the basis for a rational analysis of architectural structures and their characteristics, principles that have been interpreted and reinterpreted in the field of conservation over the following centuries.

From these initial premises, the evolution of the protection and safeguarding of historic architecture has gone through several phases, each marked by new theoretical perspectives, technological advances, and changing cultural contexts, such as those described below.

• Origins and first Reflections
  • From intuitive conservation to scientific intervention: The evolution of the protection of historic architecture has moved from an intuitive and empirical phase, based on respect for ancient structures, to a scientific approach. In the first centuries after Vitruvius, buildings were restored or kept in use without clear rules, based on oral knowledge or common sense. The gradual formulation of technical standards and criteria, beginning with the influence of figures such as Raphael, Maratta, Winckelmann, and Piranesi, led to a more systematic approach. Subsequently, with the work of figures such as Viollet-le-Duc and John Ruskin in the 19th century, a methodology for intervention in historic buildings and monuments began to be defined, either with a restorative (idealised reconstruction) or conservative (preservation of the existing state) approach.
• 19th century: Romantic Conservation
  • The 19th century saw the consolidation of the ideas of conservation and restoration as a discipline. It was a period marked by Romanticism, which privileged the reconstruction of monuments in order to restore them to their original or idealised splendour. A key milestone was the publication of the works of Eugène Viollet-le-Duc, whose rationalist and restorative approach advocated active and often creative intervention in monuments, sometimes involving the addition of elements that were not part of the original structure. On the other hand, this period also saw the emergence of criticism of these excessive interventions. John Ruskin represented a reaction against Romantic and violent restorations, advocating a more respectful, preventative conservation that accepted the passage of time and valued ruins as testimony to their history.
• 20th century: Theoretical development and institutionalisation
  • From restoration to preventive conservation: The 20th century saw a shift towards preventive conservation and minimal intervention. At the beginning of this century, conservation theories began to consolidate, influenced by the development of science and a growing respect for the historical authenticity of monuments. The foundations of William Morris and the SPAB, and the figure of Camillo Boito, introduced principles of intervention based on minimal intervention and respect for authenticity. This approach was crucial to the Restoration Manifesto of 1877, which influenced interventionist practises throughout the 20th century. However, it was the work of Gustavo Giovannoni in the 1930s that greatly influenced modern conservation theory with his approach to “integrated conservation”. His ideas combined the need to preserve monuments with respect for the urban environment and the historical context in which they are located. One of the most important milestones of the 20th century was the Athens Charter (1931), adopted at the First International Conference of Architects and Technicians of Historic Monuments, which established principles advocating the preservation of historic monuments without unnecessary alteration.
  • Post-war period: Critical theory and international letters. The post-war period saw a number of important theoretical developments. The publication of the Venice Charter in 1964 presented a more respectful approach to the authenticity of the historic building, prioritising the conservation of original materials and minimising invasive interventions. This change reflected a methodological evolution based on respect for the history and patina of monuments, rather than returning them to an idealised state that never existed. This charter consolidated the modern principles of restoration and emphasised the importance of respecting the authenticity and material integrity of monuments. It is perhaps one of the most influential documents in conservation theory and practice worldwide, laying the foundations for today’s interventions.
  • Consolidation of international regulations: Since the second half of the 20th century, the conservation of the architectural heritage has been increasingly influenced by international standards and conventions. The creation of organisations such as ICOMOS, UNESCO, and others, as well as the adoption of normative documents such as the various International Charters mentioned throughout this document, have allowed the consolidation of universal conservation criteria, albeit with room for adaptation to local contexts. This has led to a globalisation of conservation principles, where authenticity, context, and minimal intervention are considered fundamental pillars.
  • Broadening the concept of heritage: The concept of heritage has evolved from a limited view of isolated monuments of national or religious significance to a broader understanding of heritage that includes the urban environment, historic sites, and cultural landscapes. This shift has allowed conservation to focus on the interrelationship between the monument and its setting, emphasising the importance of preserving not only the buildings but also the assets associated with them.

5.2. The Impact on the Preservation of the Alhambra Palatine City

The evolution of criteria and regulations for the conservation of historic architecture has had a profound impact on the preservation of the Alhambra, a palatine city whose protection has been at the centre of the debate on interventions in historic monuments since the 19th century. The impact and influence of this evolution on the methodology applied to interventions in the Palatine City can be divided into two main periods, as described below:

• 19th century: Between the “new documentation” and the ornamental restoration.
  • The Grand Tour and documentation tourism: The period from the end of the 18th century to the end of the 19th century had a significant impact on how the Alhambra was perceived, intervened in, and preserved. Proof of this is the great documentary contribution (Grand Tour) left behind by international travellers, who documented the state of conservation of the Alhambra and its various spaces in “real time”, thus providing information specifically on the situation before, during, and after some of the most important interventions carried out in the Palatine City.
  • The ornamental restoration: For much of the 19th and early 20th centuries, the conservation of the Alhambra was the responsibility of the Contreras family, mainly through the figures of José Contreras and his son Rafael Contreras, who played a central role in important interventions carried out in the Palatine City. It was a period marked by the so-called “ornamental restorations”, which were characterised by interventions aimed at embellishing the monument according to aesthetic criteria rather than preserving its historical and material authenticity. Among its characteristics the following can be highlighted:

    -

    Orientalism and Romanticism: The interventions were inspired by an orientalist vision of the Alhambra, which was perceived not only as a historical monument, but also as a symbol of the exoticism and cultural richness of Spain’s Islamic past. This approach was aimed at satisfying the aesthetic expectations of some European visitors, who were influenced by Romanticism and sought an idealised representation in the Alhambra.

    -

    Creative reconstruction: Ornamental restorations were not limited to preserving what was left but often involved the reconstruction of architectural and decorative elements. The lack of rigorous documentation meant that many of the restored elements were not authentic, but an artistic interpretation of what was thought to be the original design. This involved the creation of ornaments, columns, plasterwork, tiled pieces, and other details that, while beautiful, did not always accurately reflect the historical state of the Palatine City.

    -

    Use of new materials: In many instances, ornamental restorers employed modern materials that were not always compatible with the existing elements, rather than attempting to preserve or consolidate the existing objects. This practice, although common in the early stages of restoration in Europe, was contrary to the principles that had already emerged, which prioritised the conservation of primary objects as historical testimony.

    -

    Scenographic approach: The focus on creating a spectacular visual experience for visitors transformed some areas of the Alhambra into carefully designed settings to convey an idealised image of the past. This had a strong tourist component, as the Alhambra began to attract large numbers of European travellers fascinated by Islamic art in the 19th century.

• 20th century: Contemporary perspectives
  • From ornamental restoration to scientific conservation: The arrival of Leopoldo Torres Balbás as architect-conservator of the Alhambra in 1923 marked a radical change in the conservation of the City. Influenced by the new theoretical currents of the 20th century, Torres Balbás introduced a scientific and archaeological approach based on respect for the authenticity of the monument and its historical context. Moving away from the romantic and creative restoration of his predecessors, who often added or rebuilt parts of the monument without a rigorous historical foundation, he focused on the conservation of the original remains, the consolidation, repair, and maintenance of the architectural object, its different rooms and its surroundings, avoiding all unnecessary interventions or those that distorted the architectural history of the City as a whole. One of the most important principles initiated by Torres Balbás is that of preventive conservation and minimal intervention, concepts that have been key to the preservation of the Alhambra. This approach has enabled, for example, the material integrity of the tiles and tiling mosaic pieces of the Palatine City to be preserved, while ensuring that the historical authenticity of the objects themselves is maintained. This encompasses the preservation of the entire collection of tiles and tiling mosaic pieces in the City, including examples of both Islamic and Christian periods of the Alhambra.

6. Conclusions

In addition to bringing together in a single document the evolution of the criteria applied to the conservation of monuments and buildings, this study has provided an opportunity to reaffirm their perennial importance in the discipline of Heritage Conservation. In particular, it has provided an opportunity to explore how the Palatine City reflects evolving philosophical paradigms and methodological practises, offering new insights into the interaction between European restoration ideologies and their application to one of Spain’s most important architectural complexes. Furthermore, it also highlights the Alhambra’s unique position as a case study and a framework contributing to advancing the scholarly discourse on heritage preservation.

In Spain, as in Italy, France, or England, the lack of an architectural tradition applied to the preservation of historic buildings and monuments has been affected by a long period of apprenticeship, until the configuration of a tutelary awareness, safeguarding, and protection of historic artistic architectural heritage. This formula, combined with collective experience, has shown, through both successes and failures, that the concern to preserve the heritage of the past will continue to be the subject of constant reflection. Likewise, the evaluation of different concepts and the existence of institutions and regulations in successive historical periods have favoured the survival of assets such as the Alhambra, considering them as part of a single universal heritage. Thus, the conservation of the Nasrid Citadel was born out of the transformations that took place during the Christian period and must be complemented by the evolution of the concepts of heritage conservation and protection that originated in Europe, since together they give rise to the contemporary idea of the monument that it possesses.