**1. Introduction**

Although often viewed as a scientific "sidecar", organic residue analysis (ORA) is gradually becoming a core component of archaeological research design, as its capacity to illuminate otherwise invisible data becomes increasingly evident. Since 2003, the ARCHEM project has collected and curated thousands of ORA field samples taken from ancient artifacts at sites across the eastern Mediterranean and western Asia, including Greece, Israel, Turkey, and Egypt. These include not only samples extracted in the field from freshly-excavated objects (typically, though not exclusively, ceramic), but also samples taken from "legacy" objects excavated up to a century prior, and stored in varying conditions in museums or excavation storage facilities. Although legacy objects do tend to yield diminished results from both a quantitative and qualitative perspective (as their compounds are subject to greater degradation), our work has demonstrated both their value and untapped potential as proxies for cultural, commercial, or environmental change when object parameters and biographies are carefully considered [1]. This is best illustrated through comparison between ORA results from freshly-excavated and legacy objects, an approach that offers valuable insight into the processes of

chemical, environmental, and anthropogenically-induced degradation that affect them; it also has significant implications for future methodologies of sample collection and interpretation.

In the comparative case study below, we present, in parallel, ORA results taken from artifacts excavated at Mochlos and Tourloti, both Late Bronze Age (LBA) sites in East Crete (Figure 1). We offer some preliminary comments on their ramifications for the variable expression of compounds, the significance of vessel topography, and the overarching value of legacy data in ORA studies as a whole. This is the second in a series of short studies undertaken with the ARCHEM library of samples integrated into the OpenARCHEM archaeometric database, a new open-access repository, resource, and publication outlet for archaeometric data [2].

(**b**)

**Figure 1.** (**a**) Map of the eastern Mediterranean. Map data **©** 2019 Google Maps. (**b**) Map of East Crete. Base map by R. Boquist. Courtesy of J. G. Younger.

## *The Tale of Two Perfumes*

In 2004, excavations at the coastal site of Mochlos in East Crete, co-directed by C. Davaras and J. S. Soles, revealed a Late Minoan (LM) IB (ca. 1500 B.C.) perfume workshop, which functioned at the height of the Minoan palaces only to be abandoned after a major LM IB earthquake [3,4]. The perfume manufacturing installation was found largely in situ, and its centerpiece was a complete circular ceramic vat (P6267), ca. 50 cm in diameter, with a specialized, detachable spout created from a conical vessel ("rhyton"); a fragmentary, undecorated oval-mouthed amphora (P6313A) was found nearby [4]. The amphora was pierced through the bottom in antiquity and may have served as a filter or volumetric standard for bottling the final aromatic product in finer, decorated amphoras. These objects were selected as good candidates for ORA given their likely role in a specialized production process, although its nature was unclear at the time. Once removed from the soil with gloves (typically nitrile) or placed directly into aluminum foil without direct contact, the artifacts were left uncleaned, packaged (some in plastic bags), and transported to the nearby Institute for Aegean Prehistory Study Center in Pacheia Ammos, where organic residues were extracted within two weeks of excavation. The goal was to minimize time between excavation and extraction, and, therefore, to reduce potential for harmful exposure. These precautions, coupled with the careful avoidance of cleaning and conservation prior to sampling, have all been shown to reduce the risk of anthropogenic and environmental contamination, alteration, and degradation while maximizing the potential for significant results [4–6]. Samples were taken according to an early version of the ARCHEM non-destructive extraction protocols described in the methodology section below.

**Figure 2.** Late Minoan IIIC Early stirrup jar from Tourloti.

In 1905–1906, during excavations of a LM III (ca. 1400–1050 B.C.) cemetery at Tourloti-Plakalona, approximately 4 km to the southeast of Mochlos, Richard B. Seager [7] uncovered a LM IIIC tomb (ca. 1175 B.C), whose contents included a locally-made stirrup jar (Penn Museum MS4494, Figure 2). This is a small globular, spouted vessel whose twin handles run from its shoulder to attach to a short "false neck" at its top, giving the appearance of stirrups. It is painted in the so-called Close style, and depicts a stylized octopus, an image descended from marine motifs popular in Minoan palatial traditions several centuries prior, but painted in a manner consistent with stylized trends typical for the early 12th century, or LM IIIC Early [1,8]. After excavation, the Tourloti jar was included by Seager in a group of local East Cretan artifacts gifted by the Candia Museum (now the Herakleion Archaeological Museum) to the Free Museum of Science and Art (now the University of Pennsylvania Museum of Archaeology and Anthropology), where it has been in storage since 1906 [9], most recently in modern, enclosed archival cabinets for the past several decades. MS4494 is almost completely intact

and completely enclosed with only a ca. 5 mm opening providing access to its interior, and—based on our inspection and according to museum records—has never been displayed, handled excessively, or cleaned aggressively (e.g., scrubbed, acid washed, immersed in water). With a permit from the Penn Museum Scientific Testing Committee, ORA samples were taken from this vessel in 2015, over a century after its original excavation, employing the most recent version of the ARCHEM extraction protocol first applied to the Mochlos objects in 2003 [1,4–6].

### **2. Materials and Methods**

OpenARCHEM prioritizes in-field and on-site extractions, for which non-destructive sampling methods are best suited. The value and viability of these approaches have been demonstrated in numerous studies [1,4–6,10–13]. Ancient organic compounds pose a challenge to the archaeological scientist in that, even under ideal conditions, they are prone to volatilization, degradation, and decomposition over time. As such, the diagnostic components of ancient compounds register more weakly than in comparable modern samples. Beyond these naturally occurring processes, archaeological samples are also susceptible to anthropogenic or environmental contamination in their journey from excavation to storage and exhibition, processes that have the potential to further obscure, dilute, or alter chemical signatures. Extraction and instrumentation protocols, if not carefully calibrated, can actually exacerbate these challenges. As such the ARCHEM project has developed and tested methodologies to maximize diagnostic output while minimizing undue risk to the already fragile contents as well as the artifacts themselves.
