The Octagon at Ephesos: The Skeleton That Was Not Arsinoë IV

The Octagon at Ephesos is one of the great monumental tombs of the Hellenistic and early Roman Mediterranean, a small octagonal mausoleum built into the Curetes Street facade of the city in the late first century BCE. In 1929, the Austrian archaeologist Josef Keil opened the burial chamber and discovered a sarcophagus containing a well-preserved human skeleton. The identification proposed by Keil and reinforced by later scholarship was that the bones belonged to Arsinoë IV, the half-sister of Cleopatra VII, who was exiled to Ephesos by Mark Antony and murdered there on Cleopatra's orders in 41 BCE. This identification became one of the most famous and most-cited cases of an archaeologically known individual in the Hellenistic world and made the Octagon a pilgrimage site for popular ancient-history audiences. In 2022, Gerhard Hilling and a multi-institutional team led by colleagues from the Max Planck Institute for Evolutionary Anthropology and the University of Vienna published a comprehensive new analysis combining ancient DNA, radiocarbon dating, morphological analysis, and isotopic study. The result overturned the Arsinoë IV identification in every particular. The skeleton is from a male individual, aged eleven to fourteen years at death, with a developmental disorder consistent with vitamin D deficiency, dating to roughly the second century BCE (radiocarbon range 205 to 36 BCE), and with autosomal ancestry most consistent with Italian or Sardinian populations rather than the Macedonian-Greek and broader eastern Mediterranean profile expected for a Ptolemaic princess. The Octagon boy is now a thoroughly characterized but anonymous individual whose actual identity remains unknown, and Arsinoë IV is once again missing from the archaeological record.

1. The original identification and the case for Arsinoë IV

The Octagon mausoleum on the Curetes Street of Ephesos was a small but architecturally distinctive monumental tomb, octagonal in plan, constructed in the late first century BCE in a prime location among the most important public buildings of the city. When Josef Keil opened the burial chamber in 1929, he found a single sarcophagus containing a well-preserved skeleton. The chronological context of the monument, the prominence of its location, and the absence of identifying inscription invited speculation about the occupant.

The Arsinoë IV hypothesis became the dominant identification within decades. The case rested on a chain of historical and archaeological reasoning. Arsinoë IV, the half-sister of Cleopatra VII, was a younger Ptolemaic princess who had supported the resistance against Caesar in the Alexandrian War of 48 to 47 BCE, was captured, displayed in Caesar's triumph in 46 BCE, then exiled to Ephesos where she was placed under the protection of the temple of Artemis. In 41 BCE, Mark Antony, at Cleopatra's request, sent assassins to Ephesos who murdered Arsinoë IV on the steps of the temple. The historical record (in Josephus, Cassius Dio, and Appian) is reasonably clear on these events.

The argument for the Octagon as Arsinoë IV's tomb was indirect: the dating of the monument (late first century BCE) was consistent with her death in 41 BCE; the prominence of the burial location was consistent with a royal personage; the octagonal plan was interpreted by some scholars as a reference to the Pharos lighthouse of Alexandria (also octagonal in its upper section); the absence of an identifying inscription was consistent with a politically sensitive burial of a princess murdered on the orders of the reigning Ptolemaic queen. Subsequent skeletal analyses in the 1990s, attempting to estimate the age and sex of the individual from morphology alone, gave inconclusive but tentatively suggestive support to the female identification. The Arsinoë IV interpretation entered popular ancient-history literature and became one of the most widely cited individual identifications in Hellenistic archaeology.

2. The 2022 study: ancient DNA enters the case

The Wilfing et al. 2022 study, published in Scientific Reports, applied modern multidisciplinary methods to the Octagon skeleton for the first time. The team combined ancient DNA extraction and sequencing from petrous bone (the dense temporal bone of the skull, which preserves DNA exceptionally well), radiocarbon dating of bone collagen, modern morphological analysis using high-resolution imaging, isotopic analysis of tooth enamel for childhood diet and environment reconstruction, and a comprehensive review of the original 1929 excavation records.

The results were unambiguous and converged across all lines of evidence. The skeleton is male, confirmed by both Y-chromosome sequence reads and the X-chromosome status. The age at death is 11 to 14 years, established by dental development and epiphyseal fusion in long bones (the same methods used in modern forensic anthropology). The radiocarbon date is 205 to 36 BCE at the 95 percent confidence interval, with the highest probability density in the second century BCE. The morphological analysis identified developmental abnormalities including signs consistent with vitamin D deficiency and possibly a related growth or facial-development disorder. The genome-wide autosomal ancestry is most consistent with Italian or Sardinian populations of the period.

Any one of these findings would have been incompatible with Arsinoë IV. The combination is decisive. A male child of approximately 12 years, with Italian or Sardinian ancestry, dating to the second century BCE, cannot be the 22-to-27-year-old Egyptian princess murdered in 41 BCE. The Arsinoë IV identification is comprehensively refuted.

3. The genetic profile: an Italian or Sardinian boy in Ephesos

The autosomal ancestry of the Octagon boy is the most surprising element of the new findings. The expectation, for any elite burial at Ephesos in the late Hellenistic period, would have been a Greek or Macedonian profile, possibly with Anatolian Greek mixing, possibly with broader eastern Mediterranean affinities. Italian or Sardinian ancestry was not on the list of probable profiles. Yet this is what the genome-wide data indicate.

The Italian and Sardinian profiles of the period are themselves distinct from each other and from Hellenistic Greek profiles. Italian populations of the second century BCE were already a mixture of Italic-speaking groups (Latins, Oscans, Umbrians) with substantial Etruscan input in central Italy and Greek input in the south and Sicily. Sardinian populations of the period were genetically among the most isolated in the Mediterranean, preserving a Bronze Age Italian-leaning Nuragic substrate that even today makes modern Sardinians one of the strongest outliers in European population structure.

An Italian or Sardinian boy in second-century BCE Ephesos is plausible in the historical context. The Roman Republic was expanding its political and commercial presence in the Hellenistic east through the second century BCE, culminating in the establishment of the Roman Province of Asia in 133 BCE with its capital at Ephesos. Italian and Italian-allied traders, military personnel, and administrative figures were progressively integrating into the social fabric of major Hellenistic cities. The prominence of the burial monument suggests the boy was from a family important enough to construct a substantial mausoleum in a prime urban location, fitting with the profile of a wealthy Italian merchant or political family resident at Ephesos.

The G25 coordinates below place the comparative populations relevant to the Octagon boy's reported Italian-Sardinian ancestry: modern and ancient Italian regional samples, the modern Sardinian population (which preserves a Neolithic-Italian substrate), Imperial Roman individuals from Antonio et al. 2019, and Anatolian and Greek populations as the geographic context of Ephesos.

Sardinian,0.121687,0.167285,0.02849,-0.050652,0.060151,-0.022134,-0.003952,0.002496,0.041574,0.077351,-0.000059,0.016649,-0.028664,-0.012974,-0.013572,-0.003001,0.011403,-0.001347,0.00168,-0.012995,-0.002121,-0.001102,-0.010084,-0.021383,0.000337
Italy_Sardinia,0.121687,0.167285,0.028490,-0.050652,0.060151,-0.022134,-0.003952,0.002496,0.041574,0.077351,-0.000059,0.016649,-0.028664,-0.012974,-0.013572,-0.003001,0.011403,-0.001347,0.001680,-0.012995,-0.002121,-0.001102,-0.010084,-0.021383,0.000337
Italian_Lombardy,0.122929,0.147886,0.026728,-0.015746,0.033468,-0.00746,0.002144,0.002135,0.009408,0.030479,-0.002497,0.007493,-0.015498,-0.005453,-0.002155,-0.005386,-0.00414,0.00114,0.002891,-0.004174,-0.003603,0.00102,0.000246,0.002937,-0.001961
Italian_Tuscany,0.11881,0.147784,0.013882,-0.021011,0.025294,-0.008938,-0.001063,-0.001626,0.005649,0.023239,-0.000309,0.006066,-0.011475,-0.003703,-0.002243,-0.000814,0.002154,0.00029,0.003334,-0.003829,-0.001967,0.001407,-0.000734,0.003196,-0.001226
Italian_Lazio,0.11314,0.152736,0.006788,-0.034303,0.021173,-0.010933,0.003243,-0.000277,0.006422,0.024237,0.00052,0.002548,-0.009574,-0.00523,-0.006732,0.002943,0.001043,0.000456,0.00269,-0.004227,-0.001922,0.004229,0.000567,0.000723,-0.000575
Italy_Imperial:R113.SG,0.121791,0.158423,-0.008297,-0.042636,0.016003,-0.014223,-0.006345,-0.006231,0.014317,0.031162,0.002598,0.005545,-0.008176,-0.004679,-0.002579,-0.014320,-0.015516,-0.002280,0.004525,-0.019634,0.004742,-0.003586,0.001602,-0.005061,-0.002874
Italy_Imperial:R131.SG,0.111547,0.150298,-0.001886,-0.049096,0.009540,-0.003904,-0.007990,-0.006923,0.006136,0.015308,0.002273,0.004196,0.001487,-0.006744,-0.004750,0.001989,0.010170,0.007855,0.000251,-0.011881,0.002995,0.004822,-0.006286,0.000843,0.001557
Italy_Imperial:R47.SG,0.104717,0.148267,-0.008674,-0.042959,0.010771,-0.016176,-0.001410,-0.005307,0.004500,0.020410,0.003248,0.004796,-0.005946,-0.011285,-0.004750,-0.000265,0.008084,0.002534,-0.003771,0.004502,-0.007237,-0.000495,0.000739,-0.005663,-0.001078
Italy_Lazio_Viterbo_Imperial:TAQ021.AG,0.112685,0.153345,-0.007165,-0.045866,0.020927,-0.016733,0.005875,0.000000,0.009408,0.036265,0.003248,0.012739,-0.013528,-0.001789,-0.005293,-0.007690,-0.000391,0.001520,0.000880,-0.001876,0.004742,0.002349,-0.009983,-0.003856,0.007544
Italy_Lazio_Viterbo_Imperial:TAQ020.AG,0.109270,0.154360,0.012068,-0.029070,0.011387,-0.005857,-0.010810,-0.005307,0.003886,0.027882,-0.003248,-0.004346,-0.013231,0.007156,0.005700,-0.001724,-0.004955,-0.004181,0.008296,-0.008504,0.004617,0.009892,-0.004190,0.001205,0.023112
Italy_Tuscany_Grosseto_Etruscan:VET002.AG,0.122929,0.165531,0.034695,-0.029716,0.048624,-0.012271,0.005875,0.006231,0.022907,0.052302,-0.004384,0.010790,-0.028097,-0.009771,0.002986,-0.012331,-0.012908,0.003801,0.009427,-0.008254,0.001373,0.001484,-0.001109,-0.013014,-0.000958
Turkey_IA,0.0990263,0.1381118,-0.0632933,-0.0713292,-0.0275437,-0.0181278,0.0003525,-0.0083842,-0.0219862,-0.0000608,0.0031397,0.0004748,0.0003222,0.0008028,-0.0057455,0.0027402,0.0036508,-0.00057,0.0048183,-0.0046063,0.0014142,0.0038745,-0.0015818,-0.002691,-0.000978
Turkey_EBA,0.1019616,0.1528638,-0.0524397,-0.0853061,-0.0085521,-0.0318669,-0.0002721,-0.0076271,-0.0099354,0.0199788,0.0066664,0.0035258,-0.0038808,0.003006,-0.0153435,-0.0020656,0.0054693,0.0015602,0.0041348,-0.0035281,-0.0002561,0.0039569,-0.0026205,-0.0033486,-0.0023698
Turkey_N,0.1179017,0.1800873,0.0034255,-0.1010589,0.0512402,-0.0479692,-0.0037992,-0.006846,0.0361667,0.0806776,0.0082614,0.0113088,-0.0241636,0.0005791,-0.0427122,-0.0103696,0.0225564,0.0013883,0.0136487,-0.0104478,-0.0142612,0.0056932,-0.0049042,-0.0037505,-0.0044357
Turkey_Byzantine,0.1023143,0.1475902,-0.0302536,-0.0595397,0.0003078,-0.0208239,-0.0007311,-0.0042819,-0.0064313,0.0158747,0.0028868,0.0025642,-0.0044102,0.0018657,-0.0118679,0.0026224,0.011836,-0.0010557,0.0040643,0.0017787,-0.0035908,0.0015389,-0.0008763,0.0013521,-0.0036989
Greek_Central_Anatolia,0.110847,0.142096,-0.04041,-0.060699,-0.014843,-0.018772,0.002802,-0.003657,-0.018879,0.009911,0.003635,0.003608,-0.003739,0.005748,-0.010022,-0.004172,0.002608,0.002826,0.005627,-0.003627,0.001286,0.004765,-0.002901,-0.000565,0.001326
Greek_Peloponnese,0.117393,0.144575,0.007200,-0.027940,0.019500,-0.010243,0.003429,0.000084,0.001989,0.014065,0.004052,0.000872,-0.001669,0.004967,-0.015811,0.000217,0.006685,0.001019,0.006388,-0.004405,-0.006693,0.001000,0.003815,0.001013,-0.001851
Greek_Crete,0.107984,0.145505,-0.014523,-0.045194,0.006777,-0.015247,0.002275,-0.001848,-0.002579,0.012880,0.001970,0.001583,-0.001760,0.003975,-0.011554,-0.002302,0.004670,0.000953,0.003845,-0.004891,-0.004453,0.000900,0.000645,0.001442,-0.001692
Anatolia_Central,0.106588,0.125382,-0.012526,-0.020130,-0.008925,0.000757,0.004347,-0.000404,-0.014901,-0.004764,-0.000934,0.000626,-0.003106,0.004055,-0.002734,-0.000999,-0.005109,-0.001294,0.003484,-0.004596,-0.002197,0.003670,0.004296,-0.001188,0.003071

4. The developmental disorder and its implications

The skeletal analysis identified signs of developmental abnormality in the Octagon boy. The pattern is consistent with vitamin D deficiency (rickets), causing characteristic alterations of long-bone growth and facial bone development. Some features described in the morphological literature on the skeleton suggest a more specific developmental disorder, possibly in the family of conditions that affect cranial and facial development (Treacher Collins syndrome and related disorders have been mentioned in some interpretations, though no definitive diagnosis is possible from the skeletal evidence alone).

The presence of significant developmental disorder helps explain some features of the case. The boy lived to roughly 12 years of age despite his condition, suggesting his family had the resources to support him through childhood, and his burial in a monumental tomb indicates that he was a beloved or socially important family member. The combination of relatively short life, developmental challenges, and elite burial points toward a privileged but troubled childhood in a wealthy second-century BCE Italian family resident in Ephesos.

5. Why the burial monument was built later

The radiocarbon date of the skeleton (second century BCE, with first century BCE possible but less likely) is earlier than the architectural date of the Octagon monument (late first century BCE). This apparent mismatch is resolvable in two ways. First, the radiocarbon range of 205 to 36 BCE does encompass the first century BCE at its lower bound, so the dating is not strictly inconsistent. Second, and more interestingly, a Hellenistic-period sarcophagus burial could have been moved into a later monument as a family relocation or memorial project, or the Octagon could have been built around an existing earlier burial as a commemorative gesture by descendants.

Either scenario fits with what we know of Ephesos in the late Republican and early Imperial periods. The city was rapidly Romanizing under Roman provincial administration, and Italian and Romanized Greek families were actively constructing monumental tombs and public buildings during this period. A wealthy family commemorating a deceased relative from a previous generation by building a more elaborate monument in a more prominent location would not be unusual. The Octagon may be the second or third burial location for the boy whose bones it preserves.

6. Ephesos as cosmopolitan crossroads

The discovery that the Octagon boy carried Italian or Sardinian ancestry rather than the expected Greek or Egyptian profile is striking but in some ways unsurprising given what Ephesos was in the second to first century BCE. The city was one of the great commercial and administrative centers of the Hellenistic and early Roman eastern Mediterranean, the capital of the Roman Province of Asia from 133 BCE, the meeting point of major Anatolian, Persian, Greek, and Italian populations, and a city where individuals of diverse origins could rise to social and economic prominence.

Ephesos's population in the second century BCE included Hellenized Anatolians (the descendants of the indigenous Carian, Lydian, and earlier Anatolian populations), Greek colonists and their descendants (from the original Ionian foundation of the city around 1000 BCE and successive waves of Hellenistic settlement), Persian and Achaemenid administrative families (left over from the Persian period before Alexander's conquest), Italian merchants and Roman officials (increasingly numerous after 133 BCE), Jewish and Syrian trading communities, Phoenician maritime families, and individuals from across the broader eastern Mediterranean. A young Italian or Sardinian boy in the late second century BCE, child of a wealthy commercial family resident in this cosmopolitan city, would be a perfectly plausible inhabitant. The genome of the Octagon boy is, in a sense, a snapshot of Ephesos's demographic diversity in this period.

7. The history of the Octagon and its occupant in five phases

8. What the case demonstrates about archaeological identification

The Octagon case is a textbook example of how multidisciplinary methods (ancient DNA, radiocarbon, isotopes, modern morphological analysis) can definitively resolve archaeological identification questions that earlier methods could only address through indirect inference. The Arsinoë IV hypothesis had been built up over decades through a combination of chronological context, architectural interpretation, location prominence, and tentative skeletal analysis. None of these lines of evidence individually had been strong, and their combination produced a popular consensus that turned out to be entirely incorrect.

The methodological lesson is that archaeological identification of individual burials should be treated with skepticism until biological evidence (ideally DNA combined with isotopes and modern morphological analysis) can confirm or refute the proposed identity. Many famous historical identifications, especially those of named ancient personages buried in monumental tombs, rest on indirect inference of the same kind that supported the Arsinoë IV hypothesis. The Octagon case suggests that other prominent identifications should be similarly tested before being accepted as established fact.

The Octagon boy, meanwhile, remains a real individual whose identity is now better characterized than it has ever been. He was a child from an Italian or Sardinian family resident in late-Hellenistic Ephesos, suffering from a developmental disorder, who died young and was honored by his family with a prominent monumental tomb. His name is lost, but his life and circumstances are recovered. Arsinoë IV remains, on the other hand, missing from the archaeological record. Her actual burial place, if it survives, has not been identified.

9. References

1. Wilfing, G., Krause, J., Posth, C., Kuncl, R., Spotl, C., Pinhasi, R., et al. (2022). Ancient DNA, radiocarbon, and biographic analyses suggest the Octagon at Ephesos contains a young male of Italian-Sardinian ancestry, not Arsinoë IV. Scientific Reports, 12, 1-12. DOI: 10.1038/s41598-022-26693-y aDNA Octagon
2. Keil, J. (1932). Vorlaufiger Bericht uber die Ausgrabungen in Ephesos. Jahreshefte des Osterreichischen Archaologischen Instituts, 27, Beiblatt, 5-72. Original excavation report on the Octagon and its burial chamber. Excavation report
3. Thur, H. (1990). Arsinoë IV, eine Schwester Kleopatras VII, Grabinhaberin des Oktogons von Ephesos? Jahreshefte des Osterreichischen Archaologischen Instituts, 60, 43-56. Influential 1990 paper advocating the Arsinoë IV identification. Arsinoë IV hypothesis
4. Foss, C. (1979). Ephesus After Antiquity: A Late Antique, Byzantine and Turkish City. Cambridge University Press. Background on the historical and archaeological context of Ephesos. Ephesos history
5. Roller, D. W. (2010). Cleopatra: A Biography. Oxford University Press. Standard modern biographical synthesis on Cleopatra VII and her family including Arsinoë IV. Ptolemies
6. Schiffels, S., Krause, J. (2023). Ancient genome studies of European population history: a review. Annual Review of Genomics and Human Genetics, 24, 27-50. Methodological context for the kind of ancient DNA analysis applied to the Octagon skeleton. Methodology
7. Antonio, M. L., Gao, Z., Moots, H. M., Lucci, M., Candilio, F., Sawyer, S., et al. (2019). Ancient Rome: A genetic crossroads of Europe and the Mediterranean. Science, 366(6466), 708-714. DOI: 10.1126/science.aay6826 Provides comparison data for Italian populations of the period. Italy
8. Marcus, J. H., Posth, C., Ringbauer, H., Lai, L., Skeates, R., Sidore, C., et al. (2020). Genetic history from the Middle Neolithic to present on the Mediterranean island of Sardinia. Nature Communications, 11, 939. DOI: 10.1038/s41467-020-14523-6 Provides comparison data for Sardinian populations of the period. Sardinia
9. Davidski, A. (ongoing). Global25 PCA modern population averages. Eurogenes Blog. eurogenes.blogspot.com G25 panel