*4.3. Discussing the Petrographic and Isotopic Analysis Results in Relation to Historical Sources, Data and Testimonies*

Mineralogical, petrographical and isotopic investigations indicate that the Holy Aedicule marble samples were quarried at the island of Proconnesos. Intra-site discrimination demonstrated that the samples are of the Proconnesos-1 variety, while further topographical investigation suggested possible quarries from which each sample could have originated from.

These results will herein be discussed in relation to existing historical data and a previous archaeometry study of mortar samples from the Holy Aedicule [69], in order to discuss the use of Proconnesian marble to enclose the Holy Tomb, as well as to decorate the interior of the Holy Aedicule structure.

It must be noted that, although historical testimonies of pilgrims visiting the Tomb of Christ throughout the centuries are of great significance, their interpretation is difficult and may sometimes be misleading or even contradictory. Usually, their intention is not to document the Holy Tomb and the structure surrounding it, but to describe this most holy site glorifying the resurrection of Christ (it is frequently addressed as "holy of holies"), while the variations in metric systems throughout the ages does not facilitate comparisons. Thus, their accounts are useful to the interpretation of archaeometric findings, however, cannot always be taken into account in a literal and conclusive manner. In Table 6, the most important historical sources and testimonies related to the presence of marble facings surrounding the Tomb of Christ in the Holy Aedicule structure, are presented in chronological order.


**Table 6.** References to the Tomb of Christ and the interior marble facings of the Holy Aedicule.


**Table 6.** *Cont*.

Historical sources and the surviving accounts of pilgrims visiting the Holy Aedicule, already from the fourth century, describe a glorious monument surrounding the Tomb of Christ adorned with marbles and other decorative features. Constantine declares his intention of bringing materials from *"all sources"*. From Eusebius's account it seems that the Tomb of Christ *"the sacred cave"* was the chief part of the whole work during the construction of the Constantinean complex and was lavishly adorned and *"brightened up"*. Historical sources reveal that Constantine and Helena brought large quantities of marble to Jerusalem [54]. Thus, according to the historical data, it is likely that the Holy Aedicule structure was adorned with marble facades from the Constantinean era, and the Tomb of Christ was cladded with marble in order to protect it.

Optical Stimulated Luminescence (OSL) dating conducted in a previous study [69] supports this theory. Indeed, the bedding mortar connecting the fragmented lower marble plate (corresponding to sample OM10) with the original burial rock surface, was found to be of an age of 1670 ± 230 years, thus the calendar centered age of 345 AD, corresponding to the era of the Constantinean constructions. The fact that a number of pilgrims speak of the Tomb as *"cut out of the rock"* is perhaps connected to the three port-holes of the vertical marble slab, which allowed visibility to the original burial rock surface itself (e.g., Abbot Daniel, in the early 11th century states *"This sacred rock, which all Christians kiss, can be seen through three small round openings on one side* ... *"*).

The cladding of the Holy Tomb with marble from as early as the Constantinean era, was obviously installed as, without protection, the pilgrims would have all cut out a piece of the rock surface of the Holy Tomb material as a keepsake. The use of white marble from Proconnesos is an excellent selection for the Tomb of Christ, as its color and texture reflect light, symbolizing regeneration, with the proper amount of required simplicity. Furthermore, as already mentioned in the Introduction section, Proconnesos marble was extremely popular and widely used in imperial buildings during the Constantinean era. Thus, the lower plate, originating from Proconnesos, was installed at the time of Constantine; it was preserved throughout the centuries, even after being fragmented, and is still present, although not visible, within the Tomb of Christ under the upper plate worshiped today.

The marble fragment (sample OM49), found within the Tomb of Christ when it was opened by the NTUA interdisciplinary team, was also determined as Proconnesian marble in this study. This fragment is of the same thickness as the lower Constantinean marble plate (~3.3 cm). The location where it was found (inside the Tomb, indicating its importance) and its identical dimension of thickness with the lower marble plate (OM10), suggests that it is perhaps a fragment of the decorative edge from the missing part of the lower plate. If this is the case, the original marble member was extracted from the quarry C5b (Table 5).

The upper plate (sample OM11), still worshiped today, is also Proconnesian marble and, as already mentioned, its surface discoloration, giving the stone an amber-hue, is related to the daily application of myrrh on the surface, as a religious ritual, continuing for centuries up to today. The upper plate, due to its position, was definitely placed at a later date than the lower Constantinean plate, however it is very difficult to pinpoint the exact date it was placed; it was probably in place by 1345 AD, as it is at that time mentioned by an anonymous English pilgrim. The presence of more than one slabs is mentioned by Bonifacio da Ragusa, as stated in Table 6, however it cannot be certain which slabs he is referring to and whether he installed the upper plate worshiped today or if it preexisted. Sample OM11 could have been quarried from a number of quarrying locations of the Proconnesos island (Table 5), thus any comparison with other samples could not lead to safe conclusions.

In any case, a marvelous continuity of material both in relation to its memory and its use, is highlighted by the fact that the two marble plates covering the Tomb of Christ, although placed centuries apart, are both marbles that originate from the island of Proconnesos.

The marble sample taken from the marble facings of the interior of the Tomb Chamber, opposite the Tomb of Christ, and in particular from a slab of the south interior wall (sample OM13), is also proven to be Proconnesian marble in the current study. In a previous study, OSL dating was conducted on a mortar behind this particular slab and found to correspond to an age of 450 ± 68 years, thus to the central calendar age of 1570, corresponding to the Bonifacio da Ragusa restoration [69]. In parallel, a mortar selected from behind a marble slab above the one examined in this study (OM13), was dated to 335AD (calendar centered age) ±235years, that is the Constantinean Aedicule.

Thus, it is highly likely that the interior of the Tomb Chamber was adorned with Proconnesian marbles from the time of Constantine. Therefore, Bonifacio da Ragusa, either substituted certain marble slabs of the Tomb Chamber facings, using Proconnesos marble in order to be consistent with the material already adorning the Tomb Chamber, or reinstalled certain marble slabs already present, which had shifted out of position or unfastened. The later is more possible, especially taking into account Horne's reference related to the Bonifacio interventions *"The said slabs had first been attached elsewhere, and then were placed here, as also the 10 small columns* ... *"*. Horne, of course, is referring to the exterior facings, however, his statement is indicative of marble members re-use as a common practice throughout the ages, which could have been applied to the interior facings as well. This complicates the interpretation and interconnection of the historical and analytical evidence related to the architectural and structural evolution of the Holy Aedicule.

OM13 is the only sample which could have originated only from one of the examined quarries and in particular from C5b. Thus, if this marble member was first installed in the Constantinean era and Bonfacio da Ragusa reinstalled it, and taking into account that the lower tomb plate (OM10) was also installed in the Constantinean era, perhaps both members were quarried from C5b, which is the only common quarry of origin for both samples. Furthermore, quarry C5b is also a common origin quarry with sample OM49, which is the marble fragment, perhaps the decorative edge of the lower marble plate, as already mentioned. However, it is certain that the marble facing slab examined (OM13) does not match with any of the possible origin quarries either of the upper tomb plate (OM11) or of the facings of the Chapel of the Angel (OM50, OM51).

The two marble samples (OM50, OM51) from the west interior wall of the Chamber of the Angel are also Proconnesian marble. The Chamber corresponding to the Chapel of the Angel, as already mentioned, is a later addition, thus the marble facings were probably installed at least after 1099 AD in the era of the Crusaders. However, it should be noticed, that their presence from much earlier, as part of the exterior marble facings of the ciborium-type earlier structure, cannot be entirely excluded. In addition, they could also have been installed at later era, either during the Bonifacio renovation or during the major reconstruction of Kalfa Komnenos in 1810. OM 50, in accordance to Table 5, could have originated from the quarries Altinta¸s, Harmanta¸s, Mandira and C6, while OM51, could have originated from Altinta¸s and Mandira. They therefore present two common origin quarries, that is, Altinta¸s and Mandira. In any case, they do not present any common quarries with OM13 and with OM49, thus strengthening interpretation that they are a later addition.

It is extremely interesting and of great archaeological importance, that throughout the centuries, Proconnesian marble was the material of choice for the interior of the Holy Aedicule, both in the Tomb Chamber and the Chapel of the Angel. The continuity of the memory of the material and its grasping symbolism survived over 15 centuries, from its first use from Constantine's architects to the time of Komnenos, whom brought a large quantity of Proconnesos marbles to Jerusalem in order to use for architectural elements throughout the Church of Resurrection [57].

Thus, one more monument is added to the long and magnificent list of important monuments adorned with Proconnesian marble. In parallel, if the need arises for replacement of slabs in the interior of the Holy Aedicule, Proconnesian marble can be selected as the most compatible material and one that carries the light from the beginning of the Holy Aedicule.

#### **5. Conclusions**

Petrographic and isotopic analysis was implemented to study the white marbles of the Holy Aedicule and the Tomb of Christ. The examined marble samples display a characteristic heteroblastic fabric, which is characterized as "mortar-type". They comprise mostly of calcite with minor presence of dolomite, micas (phlogopite, muscovite), apatite and pyrite. Their MGS values range from 1.6 to 2.3 mm, gathered mostly around 2 mm. Their isotopic signature is characterized by δ18O values ranging from <sup>−</sup>2.49 to <sup>−</sup>1.13 (‰ V-PDB) and by <sup>δ</sup>13C values ranging from 2.43 to 3.37 (‰ V-PDB). The techniques employed proved to be adequate for the identification of their provenance and the aforementioned data suggest that the Holy Aedicule white marbles examined herein, originate from the island of Proconnesos and in particular they belong to the variety type Proconnesos-1.

Furthermore, an intra-site discrimination was attempted by comparing published MGS values and isotopic analysis data of Proconnesos quarries, with the respective data of the Holy Aedicule samples as measured herein. These results in correlation with historical data, allows for further interpretations. The fragmented lower marble plate (corresponding to sample OM10), is in fact the initial cladding of the original burial rock surface attributed to the Constantinean era. The marble fragment (sample OM49), found within the Tomb of Christ, which presented the same thickness as the lower Constantinean marble plate, is perhaps a fragment of the decorative edge from the missing part of the lower plate; if this is the case, the original marble member was extracted from the quarry C5b, which is the only common quarry between these two samples. The upper plate of the Tomb (sample OM11), was added several centuries later, however, no definite conclusion regarding the era that it was placed can be drawn; furthermore, intra-site discrimination could not provide any safe conclusions regarding the exact Proconnesos quarry it originated from.

The marble sample taken from the marble facings of the interior of the Tomb Chamber, opposite the Tomb of Christ (sample OM13) was most probably placed into its current position at the time of the Bonifacio da Ragusa restoration, without excluding the possibility that this member was present from the Constantinean era, since marble members re-use was a common practice throughout the centuries. The particular sample could have originated only from the ancient quarry C5b. The two marble samples (OM50, OM51) from the west interior wall of the Chamber of the Angel, were collected from marble members, which were placed probably during the Crusaders construction phase, without, however, excluding the Bonifacio renovation or even the major reconstruction of Kalfa Komnenos in 1810. Altinta¸s and Mandira are the only common origin quarries for these two samples and it is definite that they could not have originated from the same quarry as OM13 and OM49 (C5b).

Hopefully, the discussion made in the current research, interconnecting the results with aspects and events of the Holy Aedicule's construction history, will assist in revealing its evolution. It is extremely interesting and of great archaeological importance, that throughout the centuries, from the Constantinean era up to the Komnenos restoration, Proconnesian marble, and in particular the Proconnesos-1 variety, was the material of choice both for the cladding of the Holy Tomb, as well as for the interior facings of the Holy Aedicule.

**Author Contributions:** A.M. scientifically supervised and coordinated all aspects of the presented research; E.T.D. and M.A. conducted the in-situ investigation and sampling, conducted the correlation of the research results with the historical sources and data; A.K. assisted in the preparation of the original draft regarding the historical data; C.P. and G.E. conducted and evaluated the mineralogical and petrographical investigations; C.M. evaluated the isotopic analyses and correlated mineralogical, petrographical and isotopic data; E.T.D., M.A. and C.M. conducted the original draft preparation, as well as the writing-review and editing of the manuscript.

**Funding:** This research received no external funding. It is a pro bono post-program research, following the rehabilitation of the Holy Aedicule, aiming to shed light on the construction history and highlight the values of the Holy Aedicule.

**Acknowledgments:** The study and the rehabilitation project of the Holy Aedicule became possible and were executed under the governance of His Beatitude Patriarch of Jerusalem, Theophilos III. The Common Agreement of the Status Quo Christian Communities provided the statutory framework for the execution of the project; His Paternity the Custos of the Holy Land, Archbishop Pierbattista Pizzaballa (until May 2016—now the Apostolic Administrator of the Latin Patriarchate of Jerusalem), Fr. Francesco Patton (from June 2016), and His Beatitude the Armenian Patriarch of Jerusalem, Nourhan Manougian, authorized His Beatitude the Patriarch of Jerusalem, Theophilos III, and NTUA to perform the project. Contributions from all over the world secured the project's funding. Worth noting Mica Ertegun's and Jack Shear's donations through WMF, Aegean Airlines et al. The interdisciplinary NTUA team for the Protection of Monuments, Em. Korres, A. Georgopoulos, A. Moropoulou, C. Spyrakos, Ch. Mouzakis, were responsible for the rehabilitation project and A. Moropoulou, as Chief Scientific Supervisor, was responsible for its scientific supervision.

**Conflicts of Interest:** The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, or in the decision to publish the results.
