silver. This individual was probably a merchant or official in service of the Babylonian court. Thamūd is also mentioned in Classical sources. Surviving quotations from Agatharchides's On the Erythrean Sea, from the second century BCE, reports that the Thamud Arabs then inhabited a "stony and large shore" of the Arabian coastline, south of the Gulf of Aqaba. In a somewhat muddled passage, Pliny the Elder, a Roman historian of the first century CE, appears to locate the Thamūd at the unidentified inland town of "Baclanaza". Ptolemy, who lived in the second century, wrote that the "Thamuditai" tribe inhabited the Red Sea coastline, and that the "Thamoudenoi" tribe lived in inland northwestern Arabia—either or both may be references to the Thamūd—while his contemporary Uranius believed that the Thamūd neighbored the Nabateans. The Thamūd also joined the Roman armies as auxiliaries, and the Notitia Dignitatum mentions two units of Thamūd warriors serving the Roman Empire, one in Egypt and the other in Palestine. The Thamūd are infrequently mentioned in contemporary indigenous Arabian sources, although two Safaitic inscriptions carved some time between the first century BCE and the fourth century CE refer to "the year of the war between Gšm and the tribe of Thamūd [snt ḥrb gšm ʾl ṯmd]". An important exception is a temple at al-Ruwāfa in northwestern Saudi Arabia, built by the Thamūd themselves in the 160s CE. The temple inscriptions (in Ancient Greek and Nabataean Aramaic) state that it was constructed by a priest named Šʿdt of the "Thamūd of Robathū" for ʾlhʾ, apparently the patron deity of the tribe, with the Roman government's support. Robathū is likely the ancient name of modern al-Ruwāfa. The Thamūd in question were Roman auxiliary troops, as the inscription states explicitly: For the well-being of the rulers of the whole world... Marcus Aurelius Anthoninus and Lucius Aurelius Verus, who are the conquerors of the Armenians. This is the temple that was built by the tribal unit of Thamūd, the leaders of their unit, so that it might be established by their hands and be their place of veneration forever... with the support of Antistius Adventus, the governor. But despite the presence of a tribe called the Thamud as late as the fourth century, sixth-century Arab poets whose works are preserved in post-Islamic sources were already referring to the Thamud as an ancient and long-lost tribe whose very name recalled the transience of all