Revealing tattoo traditions in ancient Nubia through multispectral imaging

Significance

We conducted a systematic survey for tattoos among 1,048 individuals from Sudan (c. 350 BCE–1400 CE) and documented 27 individuals with tattoos—almost doubling the known number of tattooed individuals from the ancient Nile Valley. Microscopic imaging and the distribution of these tattoos demonstrate a shift in tattoo practices during the Christian period, including tattooing on children under age three. Extensive tattooing at Kulubnarti attests to the earliest evidence for Christian tattoo traditions in northeast Africa and may be ancestral to modern Christian practices in the region. Overall, this research suggests that ancient tattoo practices were more widespread than indicated by previous research, necessitating additional systematic surveys of tattoos using multispectral imaging in anthropological research collections and excavations.

Abstract

Evidence for tattooing in ancient Nubia is long-standing, although no systematic studies have compared application techniques, motifs, and the demography of tattooed individuals. We surveyed 1,048 Meroitic to medieval (c. 350 BCE–1400 CE) human remains from Semna South (n = 589), Kulubnarti (n = 406), and the Qinifab School site (n = 53). We recorded where skin preservation was sufficient for tattoo observation and used multispectral imaging methods to identify motifs and application techniques. We documented tattooing in 27 individuals of both sexes, ranging from infants to older adults. A shift in both motifs and methods used is apparent in the medieval Christian period. With at least 19% of Kulubnarti individuals displaying tattoos, this investigation demonstrates the importance of systematic surveys to detect tattooing and illuminate varying practices over time.

Tattooing is a cultural practice used by human societies throughout history to permanently mark identity, life experiences, health histories, and beliefs. Tattoos have been documented on desiccated human remains from at least 50 sites worldwide (1) showing direct archaeological evidence of these practices across continents and over the past 5,000 y.

One pivotal region seeing a growth in tattoo studies is the Nile Valley. While the presence of tattooing in the Nile Valley was already known in the late 19th and early 20th centuries (2–4), this early research identified very few examples of mummified or desiccated remains with tattoos. The advent of multispectral imaging has since made it possible for tattoos to be identified in archaeological fieldwork and institutional collections, with 30 published tattooed individuals in the broader Nile Valley (Fig. 1) that critically connect tattooing with gender, religion, and possibly medicine (5–9). These more recent studies suggest a difference in tattoo styles between human remains from ancient Egyptian and ancient Nubian contexts (10). However, these results span diverse locations and periods ranging over 800 kilometers and 4,000 y, making it difficult to identify whether and how practices change across periods, locations, religions, and demographics. The limited and sporadic evidence for tattooing prevents more refined analyses to discern cultural norms for the practice such as the techniques used to apply tattoos and ages at which individuals received tattoos. Consequently, while several examples of tattoos are documented from the Nile Valley, they remain sparse and siloed case studies.

Fig. 1.

Map of Nile Valley archaeological sites with published evidence of tattooing. Black circles indicate previously published tattooed individuals. White circles indicate published results in this study and gray circles include both previously and current published individuals. Circle size is indicative of the number of tattooed individuals per site with a total range of 1 to 23 individuals.

In this study, we use multispectral imaging techniques to survey 1,048 individuals from archaeological sites located in modern Sudan to identify the presence, distribution, and demographics of tattooed individuals. Human remains date from the Meroitic period to the Medieval period (350 BCE to 1400 CE) and range across three archaeological sites—Semna South, Qinifab School, and Kulubnarti. Human remains vary in age and sex, with neonates to elderly adults represented. Remarkable skin preservation among human remains from Kulubnarti allows a more detailed determination of the significance and ubiquity of tattoo practices. Near-infrared microscopic imaging reveals information about the tools and methods used in the Nile Valley.

Results

This survey documented 27 individuals with definite or possible tattoos (Dataset S1), including extensive examples of tattooing in the Christian-era site of Kulubnarti, despite no prior identification of the practice. We did not identify any tattoos at the Qinifab School site. Two individuals were known to have tattoos at Semna South, but our survey identified two additional examples of tattoos from the site. These findings almost double the total published sample of individuals with tattoos in archaeological contexts from the broader Nile Valley. Near-infrared imaging noticeably improved the visibility of tattoos identified at Semna South and Kulubnarti (SI Appendix, Figs. S1-S2). Microscopic images of tattoos also reveal a change in practices before and after the introduction of Christianity to the region.

Tattooing Traditions in Meroitic and Ballana Period Nubia.

A survey of human remains from Semna South—where the vast majority of individuals date to the Meroitic (c. 350 BCE–350 CE) and Ballana (c. 350–550 CE) periods—revealed a minimum of four tattooed individuals, though this value likely underestimates the frequency of tattooing. Human remains from Semna South were generally skeletonized. Among crania, only 27% (87/322) had observable skin and most of those cases were poorly preserved (patches less than 5 × 5 cm). Among infracranial remains, 47% (95/296) had observable skin; similarly, most consisted of only small patches of preserved skin on one or two elements. Consequently, skin preservation was too poor to be able to compare trends in demographics or body placement.

Prior research identified tattoos on the hands and forearm of two individuals from burial N-247, a grave with commingled elements that represent two adults and seven preadults (5, 11). The first set of hands and a left forearm belonged to a 40 to 45-y-old female. The second set of hands belonged to an adult who was possibly female (SI Appendix, Fig. S3). These tattoos consist of dotted patterns forming several series of lozenge shapes and plant-shaped motifs. Similar patterns have been evidenced in other examples of Nubian tattooing during the Meroitic period and in Egyptian Middle Kingdom (2000–1640 BCE) individuals (10). Tattoo patterns from N-247 are also comparable to Ballana period tattoos identified by Armelagos on the arm and upper leg of an adult male from site 24-I-3 at Wadi Halfa (12, 13).

We identified evidence of tattoos on individual M-046, a 17 to 21-y-old female who lived during the Meroitic period. Skin samples from M-046 appear to originate from the right lower forearm, wrist, and hand. Tattooing present on M-046 includes a band at the wrist composed of two lines of dots, a pattern of dots of unknown shape, and two bands of lozenge-shaped dot tattoos (Fig. 2). These motifs are comparable to other examples of patterned dot tattoos from Nubian human remains at Aksha (14) and those from N-247 also located on the forearm.

Fig. 2.

Tattooing on individual M-046, a 17 to 21-y-old female from the Meroitic period. Patterns of tattooed dots photographed in near-infrared light (850 nm) on a skin fragment from the right, lower forearm (below). Impressions of the radius allow for a reconstruction of the location of the tattoos as indicated (above).

We also identified tattooing on two skin fragments from individual M-285, estimated to be a female, age 50+, and dating to the Ballana period. It is unknown from which region of the body the skin fragments originated; tattoo patterning and skin texture appear similar across the fragments, suggesting they are from the same region, but the two fragments do not articulate (Fig. 3). The tattoos create two to three curved, intersecting dotted lines. Individual tattoos are far larger than those documented in N-247 and M-046, measuring up to 5 mm in length and 3 mm in width. The shapes of individual tattoos vary with some appearing more oblong than the round dots seen in N-247 and M-046.

Fig. 3.

Tattooing on individual M-285, a 50+ female from the Ballana period. Tattoos form patterns of intersecting lines with larger average dot size (3 to 5 mm) than comparable examples. The skin fragments do not articulate and are from an unknown region of the body.

Microscopic reexamination of tattoos under infrared of all four individuals allowed us to evaluate tattoo techniques and tools. Tattoos had irregularly placed clusters of darker pigment within individual dots, suggesting that tattoos were made using a single pointed tool that was repeatedly poked into the same region to fill in the tattoo (Fig. 4). Points of darker pigment are around one millimeter in diameter, indicating the approximate size of the tool tip.

Fig. 4.

Near-infrared (940 nm) microscopic images of tattoo marks. Tattoo marks on the right hand of a 40 to 45-y-old female from Semna South N-247 (A); skin fragments from Semna South M-46 (B); skin fragments from Semna South M-285 (C); the forehead of Kulubnarti 21-S-46 B124 (D). White arrowheads indicate clusters of darker pigment possibly indicating toolmarks.

Despite larger-sized tattoos overall in M-285, microscopic images suggest tools and techniques were similar to those used to create the tattoos in N-247 and M-046. Additionally, on M-285 and N-247, some tattoos are more faded than others, indicating a palimpsest of tattooing events with the same region tattooed multiple times with similar patterns.

Changing Tattoo Traditions During the Early Christian Period.

The area of Kulubnarti included two cemeteries that were used primarily from 650–1000 CE, after the introduction of Christianity to the region. We observed 190 individuals from cemetery 21-R-2 and 216 individuals from cemetery 21-S-46 at Kulubnarti. There was far better skin preservation at Kulubnarti than other sites, with skin preserved on 89% (170/190) of individuals from 21-R-2 and 74% (159/216) of individuals from 21-S-46. Skin preservation was highest in the feet and lower legs. It was lowest in the neck, thorax, and pelvis.

We identified 17 individuals with definite tattoos and 6 individuals with possible tattoos—areas of higher contrast in infrared that appear similar to known tattoos, but which are too faded or fragmentary to discern a clear pattern. Varying preservation demonstrated these are true tattoos as, in some cases of definite tattoos, pigment was visible in areas where the epidermis was eroded and simultaneously absent where bone was exposed (SI Appendix, Fig. S4), demonstrating that pigment was deposited in the dermis to form a permanent mark.

Despite relatively lower skin preservation rates in the face and forehead, 15 of these individuals had tattooing on the forehead and 11 had tattoos on the temples or cheeks. Two individuals had tattoos on the back near the mid-thoracic vertebrae and one had a tattoo over the eyebrow. Of those with observable skin on the face, 19% (23/124) were tattooed; however, in many cases, even if facial skin was present, it may not have been preserved in the exact regions that were tattooed. Consequently, at least 19% of people were tattooed at Kulubnarti, but this value underestimates the true prevalence of tattooing.

The presence of tattooing on infants and toddlers demonstrates that tattoo practices at Kulubnarti marked individuals in a permanent, public, and highly visible way in their first years of life. The youngest individual with definite tattoos was 18 mo old; possible tattoos were also observed on an infant 7.5 to 10.5 mo old. One three-year-old female (Kulubnarti 21-R-2 B60) has one tattoo pattern positioned over an existing tattoo (SI Appendix, Fig. S2); the palimpsest demonstrating that, by age 3, an individual could have been tattooed twice. Most individuals who we identified with tattoos were children under 11 y old (n = 18). However, this age distribution reflects preservation bias as the cemeteries contain more burials with preserved facial skin for those under 16 (n = 90) than 16+ (n = 30).

The presence, location, and tattoo patterns identified at Kulubnarti were not clearly associated with sex. Among individuals for whom sex could be estimated, tattoos were identified on both male (n = 5) and female (n = 7) individuals. Tattoos located on the forehead, temples, and cheeks were found across sexes and, similarly, various tattoo patterns were present on both males and females.

Four patterns were evident among the tattoos at Kulubnarti that all consisted of dots or dashes (SI Appendix, Fig. S5). First, four dots frequently were tattooed in a diamond pattern (n = 16), often found on the forehead. This motif was modified to include two diamonds placed vertically with a line of dots below in three individuals. Second, several individuals also had four dots or dash tattoos arranged in a square shape (n = 3). This pattern appeared exclusively near the temples and sometimes was duplicated with two dashes placed next to each other at each corner. Third, in three cases, individuals had multiple lines of dots on the forehead. One of these individuals had a palimpsest of this design with the four-dot diamond pattern above it (Fig. 5), indicating both motifs could be present on the same individual. Similarly, individuals with four dots in a diamond on the forehead also had four dashes in a square on the temples. Fourth, a simple line of dots was used either in conjunction with the four-dot diamond pattern (n = 3) or on its own (n = 1).

Fig. 5.

Near-infrared (850 nm) photograph of Kulubnarti 21-R-2 B144. Palimpsest of tattoo marks on a 30 to 39-y-old female displaying a pattern of dispersed lines of dots more faintly, above which was placed a diamond four-dot tattoo.

In addition to differences in tattoo patterns and locations, microscopic examination of tattoos from Kulubnarti suggests tools and techniques changed by the early Christian period. Infrared microscopic images revealed no evidence of internal structure within tattoo dots, suggesting tattoos were made from a single puncture. Also, unlike earlier tattoos at Semna South, those at Kulubnarti were more often oblong with bilateral tapering on either end (Fig. 4). This distribution of pigment is more comparable to incised tattoos rather than hand-poked and may have been produced from a single puncture (e.g., a knife point).

Despite the clear evidence for tattooing during the early Christian period in Kulubnarti, we did not identify any tattoos among the Christian period human remains from the Qinifab School site (UCSB 03-01). Most of these individuals were too skeletonized to be observed for tattoos; only 34% (18/53) had any observable skin. Frequently, only one or two elements could be observed. Skin was most frequently observable in the hands and feet. The lack of evidence for tattooing in this site may be due to poor preservation.

Discussion

These data demonstrate a broader community of practice in the Nile second cataract region (Fig. 1) during the Meroitic and Ballana periods that changed dramatically by the early Christian period. In Aksha (14), tattoos include repeated motifs of dotted diamonds across the body, crisscross patterns on the hands, and larger dots similar to those seen in the four tattooed individuals from Semna South. Additionally, tattoos from a Ballana period male identified near Wadi Halfa (12, 13) mirror those seen on hands from Semna South N-247. The interpretation of these tattoos remains difficult to discern because of the sparse examples and abstract nature of their design, but parallels exist in ceramic decoration (10, 12).

Tattoos create permanent and visible marks potentially signifying a shared set of identities or beliefs in second cataract communities during the Meroitic and Ballana periods. Previous research has drawn parallels further, finding commonalities between the geometric motifs found in the second cataract area and tattoos found on human remains from Deir el-Bahri and Kubban, with the former dating over 2,000 y before the Meroitic period (10). These tattoos may signify a shared ethnic identity, shared beliefs, or other cultural commonalities across these sites. Additionally, tattooing in these communities is predominantly, though not exclusively, found on mummified remains estimated to be female. At Aksha, only one individual with tattoos was estimated to be male, and those tattoos were found exclusively on the face rather than the more extensive tattoos on the chest and limbs of several individuals estimated to be female and the individual identified as male from the Wadi Halfa area. Tattoos at Semna South were found exclusively on those estimated to be female. These sex-based differences may indicate that the nature and placement of tattoos was gendered, but additional data are needed to understand these differences.

Extensive evidence of tattooing at Kulubnarti during the early Christian period, however, displays distinct differences in practices. The location, methods, tools, and motifs vary considerably from earlier examples, indicating a cultural shift in the use and application of tattoos by as early as the 7th century CE. This new tradition may have been part of a broader shift in tattooing across the Makurian kingdom since a 12th-century wall painting from Faras (Sudan National Museum 24362) shows a possible queen of Makuria with an x-shaped tattoo on the forehead (15). Tattoos at Kulubnarti also vary in imagery and location when compared to contemporaneous tattoos identified further south in Ghazali (16) and et-Tereif (17), suggesting that these changes were not universal across Nubia during the early Christian period. Instead, Kulubnarti tattooing focused on highly visible locations on the face and used tools, patterns, and techniques that could be employed quickly. This practice may be explained by the fact that tattooing was performed on young children, where it may have been more difficult to pattern complex imagery requiring an individual to stay still for extended periods of time.

Tattooing at Kulubnarti may represent the earliest documented iteration of Christian tattoo traditions found today across Egypt, Sudan, and Ethiopia where the forehead has frequently been used for tattoos of the cross to mark Christians permanently as believers. During the 12th to 13th centuries, four foreign accounts describe Christians from northeast Africa branding their foreheads and cheeks or temples with a cross (18–21). Oliver von Paderborn specified that Nubians branded a cross on the foreheads and temples of children and Marco Polo described this practice as a means to be distinguished as Christian (21). These accounts frequently describe using hot irons to mark the face, though there is debate over the extent of these practices and whether they were tattooing, branding, or scarification (22). Considering more recent evidence, during the 19th century, Copts were also tattooed on the forehead (22) and, in Ethiopia today, tattoos on the faces, necks, and hands of mostly women from northern regions (i.e., Tigray, Gondar, and Gojjam) often include depictions of Christian crosses (23).

The locations of the tattoos, their prevalence among young children, and the application of tattoos multiple times to the same individuals, may also indicate they were part of a medicinal treatment or ritual, possibly related to high fevers or headaches. These symptoms are commonly experienced in malaria, which is most severe in children under age 5 today (24). Evidence for malaria is longstanding in the Nile Valley (25–28). If tattoos were medicinal, then the tattoos along the thoracic spine in two adults, which is an otherwise undocumented location in other tattooed individuals from the Nile Valley, may have been made to mitigate back pain. Few historical sources document medieval medical traditions in ancient Nubia. Medieval Coptic medical texts describe applying charcoal ointments to the forehead (29), though they do not mention tattooing, scarification, or branding.

Across North Africa, tattoos have taken on multiple meanings that could include both religious and medicinal purposes, suggesting these interpretations may not be mutually exclusive and may complement other functions. Ethnographic studies in North Africa indicate tattoos in the 20th century could be decorative, protective, medicinal, and religious. For example, in 20th-century Egypt, dot tattoos on the face could mark an individual as Arab, cure a toothache, or protect women and children after childbirth (30). Even among Egyptian Copts, tattoos of a cross on children were sometimes done to address sickness (31) and some non-Christian Egyptians used this same design, indicating its use transcended Christian symbolism (31, 32). Among the Coptic Amhara in Ethiopia, tattooed circles and crucifixes on the forehead and temples were applied to prevent recurrent headaches while simultaneously serving to enhance an individual aesthetically (33). Tattoos in the form of dots among Egyptian workmen were noted by Meyers (31) to be for ornamentation and relief of pain when placed over the affected area, a practice affirmed by Field (32) in his survey of villagers in the Fayum. These sources also note that tattooing was sometimes done during childhood.

The presence of dot and geometric tattoos and their use medicinally across Libya and Morocco bear many similarities to Egyptian tattoos in the 20th century, raising the question of whether there are shared origins to 20th-century North African tattoo practices (31, 32, 34, 35). However, given the geospatial and temporal distances between these populations, more research is needed to identify whether, when, and how these tattoo traditions are linked. Our research provides crucial connections between tattooing in the medieval and modern periods in the Nile Valley, helping to fill these temporal gaps.

The results of this investigation illustrate the importance of systematic surveys for tattooing in ancient populations. The 27 tattooed individuals documented in this study almost double the previous total number of published tattooed individuals documented for the history of the Nile Valley (n = 30). Most of the tattooed individuals came from two cemeteries at Kulubnarti, where—despite extensive previous bioarchaeological research—tattooing was unknown. The volume of tattooed individuals and the presence of tattooing on individuals in their first years of life demonstrate that tattooing was prevalent in this community. At least 1 in 5 individuals was tattooed, and both males and females at Kulubnarti were tattooed relatively evenly. Given the ubiquity of tattooing at Kulubnarti, these data demonstrate that dedicated surveys of tattooing are necessary to evaluate the presence and prevalence of tattoo practices in past populations.

Materials and Methods

Archaeological Context.

Semna South, in northern Sudan, was the site of the southernmost fortification in a series built by Egyptians between the second and Semna cataracts during the Middle Kingdom. This fortress and its surroundings were the focus of the University of Chicago’s Oriental Institute Expedition during the UNESCO International Campaign to Save the Monuments of Nubia, arising from construction of a new, higher dam south of Aswan, Egypt. This work was conducted in cooperation with and licensed by the Sudan Antiquities Service (known as the National Corporation for Antiquities and Museums since 1991). A cemetery north of the fortress was excavated during fieldwork between 1966 and 1968. This cemetery was used by local Kushite (ancient Nubian) people during the Meroitic period, continuing into the medieval period. Approximately 560 graves with more than 800 individuals were excavated (36). An anatomist and a physical anthropologist completed burial documentation and estimated the sex and age of the individuals excavated during the fieldwork. A temporal designation was provided in the field based on grave style and accompaniments. Partial skeletons, some with adhering tissue, were exported to the University of Chicago along with artifacts as part of the agreement to partition collections with Sudan for participation in the rescue work. Hands, feet, ribs, and ossa coxae are generally lacking. Some individuals are represented only by a skull or vertebral column. The Semna South assemblage was moved with Dr. Charles F. Merbs from Chicago to Arizona State University in the early 1970s. It includes 517 individuals from the Meroitic period, 54 individuals from the Ballana period, and 18 from the medieval (Christian) period. Burial records and human remains from Semna South are housed in the School of Human Evolution and Social Change at Arizona State University.

Multiple sites in the area around Kulubnarti were also recorded and excavated as part of the UNESCO campaign, beginning in the 1960s, under license from the Sudan Antiquities Service. Kulubnarti is situated just below (north) of the Dal Cataract in the rugged area known as the Batn al-Hajar or “Belly of Rocks.” Two cemeteries were investigated initially by William Y. Adams in 1969 and subsequently excavated as a joint University of Kentucky-University of Colorado Expedition directed by Dennis P. Van Gerven in 1979 (37). One cemetery, 21-R-2, was located on the mainland area, while 21-S-46 was on what was then an island separated from the mainland. The excavated individuals were sent to the University of Colorado, while grave accompaniments were sent to the University of Kentucky as a gift from Sudan for participating in the rescue work. The human remains and field records from burial excavation were transferred to the School of Human Evolution and Social Change at Arizona State University in 2017, while most field photographs along with artifacts, including textiles from burial shrouds, had been transferred previously by Adams to the Department of Egypt and Sudan at the British Museum. Published radiocarbon dates demonstrate that both cemeteries were in use simultaneously, principally during the 7th through 9th centuries (38).

The Qinifab School site is located well upstream of Semna South and Kulubnarti, between the fourth and fifth cataracts of the Nile River, west of Abu Hamad, Sudan. Fieldwork at the Qinifab School site was directed by Dr. Brenda Baker between 2007 and 2009 as part of the Merowe Dam Archaeological Salvage Project, an international rescue mission. All work complied with US Office of Foreign Assets Control (OFAC) licenses (SU-1897, SU-2122) that authorized work in Sudan and import of excavated material. Fieldwork was conducted in cooperation with and under licenses issued by Sudan’s National Corporation for Antiquities and Museums (NCAM) and with permission of the local government (registration with the government and police of River Nile state in Abu Hamad) and with the local communities, Qinifab school headmaster, and landowners where the work was conducted and field team was housed. Although once a continuous cemetery, it was separated by agricultural fields and a date palm grove, creating eastern (UCSB 03-01) and western (UCSB 03-02) portions (39). The combined components form the largest of the later Meroitic through medieval cemeteries in the project area. Of the 103 individuals excavated, 100 are available for study at Arizona State University (ASU). Graves were assigned a temporal affiliation through a combination of grave styles, accompanying ceramics and objects, and radiocarbon dating, which indicate use from the end of the Meroitic period through the medieval (Christian) period from c. 250–1400 CE (39). Only the Christian period remains or those of unknown period were included in this study due to the preservation of tissue for many individuals, which was absent entirely in earlier burials. This difference is due to the lack of disturbance of almost all medieval graves, likely due to the paucity of objects interred with the deceased. The medieval graves generally consist of small ovoid to oblong rock cairns above a rectangular shaft oriented on an east–west axis, with bodies typically wrapped in a shroud and laid in an extended supine position. Most of the medieval burials were found in three geospatially defined grave clusters in the northeast portion of the site, all of which were radiocarbon dated to the Early Christian phase (calibrated calendar dates range from 657–832 CE), though a separate concentration in the southwestern portion of the eastern dated to the late Christian phase (1396–1449 CE; 39). Human remains were sent to ASU with export permits issued by NCAM under OFAC licenses and required OFAC loan agreements in 2007, 2008, and 2009. The exported artifacts and remains were gifted by NCAM to ASU in 2018, after removal of US government sanctions and are cared for by Dr. Brenda Baker along with project records in the School of Human Evolution and Social Change.

This study includes all observable human remains from the Semna South cemetery (n = 589), both Kulubnarti cemeteries (n = 406), and the Christian-era and temporally undetermined burials from the Qinifab School site (n = 53). Lists of demographic data, skin inventories, and assessments for tattooing per individual can be found in Datasets S2 (Semna South), S3 (Kulubnarti), and S4 (Qinifab School Site).

Methods.

For each individual, we reviewed whether and where skin preservation was sufficient to observe for tattoos. Criteria included 1) whether skin was present in patches large enough (approximately 2 × 2 cm or larger) to distinguish tattoo ink from surrounding skin; and 2) whether the epidermis and/or dermis are preserved without obstruction from overlying material. We created an inventory of each individual studied and indicated whether and which region of the body skin was observable (Datasets S2–S4). We photographed observable skin in visible light and recorded a photo log to associate photographs with a brief description and site/burial numbers.

For any observable skin, we scanned whether tattoos were present using the Occipital Structure Sensor on an iPad mini 2 tablet. The Occipital Structure Sensor has a built-in infrared light and sensor that have previously been used successfully to identify tattoos in human mummified remains (8). For any individuals with tattoos present, we then photographed them using a digital camera (Olympus OM-D E-M10 Mark II) that has been converted to full spectrum. This camera was modified by removing the internal UR blocking filter (low-pass filter/hot-mirror filter) and replacing it with a clear filter, allowing the camera to capture the entire light spectrum. Photographs of tattoos were taken with on-lens filters in the infrared spectrum (850 nm) and visible light spectrum (420 to 680 nm). Photographs were taken with the aid of an LED infrared external light (850 nm). Finally, tattoos were photographed using an infrared Dino-Lite microscope (AM4115FIT) to obtain more detailed images that can be compared with experimental tattoo results to evaluate what techniques and tools could have been used (40). This includes comparing internal structure, pigment separation, and edge profiles of tattoo marks. If necessary, selected photographs were further edited within ImageJ© using the DStretch® plug-in following the DStretch Tattoo Protocol (41).

We refined age and sex estimations of all individuals identified with tattoos (Dataset S1). Sex estimations included observations on gross morphology of the skull and pelvis (42), maximum femoral head diameter, observable genitalia, and aDNA (38). Age estimations were refined based on epiphyseal fusion and dental development in preadults (43, 44). Adult age estimations were based on observations of the auricular surface and pubic symphyses (42).

Supplementary Material

Appendix 01 (PDF)

Dataset S01 (XLSX)

Dataset S02 (XLSX)

Dataset S03 (XLSX)

Dataset S04 (XLSX)

Data, Materials, and Software Availability

Study data are included in the article and/or supporting information.