A rich oasis city at the inland end of a pass in Syria and the modern capital of Syria. Damascus was occupied by the 3rd millennium BC, but the settlements of the prehistoric, biblical and Roman periods underlie the modern and medieval city and are therefore not readily available for excavation. Excavations have demonstrated that an urban center existed in the 4th millennium BC at Tall as-Salhiyah, southeast of Damascus. Pottery from the 3rd millennium BC has been found in the Old City. Before the 2nd millennium BC an intricate system of irrigation for Damascus and al-Ghutah had been developed. Egyptian texts and references in the Bible attest the city's importance in international trade from the 16th century BC; it appears as Dimashqa in the Tell El-Amarna documents. The Aramaeans conquered Damascus in the late 2nd millennium BC and it was subsequently annexed by the Israelites (10th century BC) and later the Assyrians (8th century BC). By 85 BC it had become capital of Nabatean kingdom; by 64 BC it was a Roman city of commercial and strategic importance, and subsequently a major Byzantine garrison. Damascus was captured by the Arabs in 635 and chosen as their capital by the Ummayads, who formed the first Islamic dynasty and ruled from 661-750. Its most famous Islamic monument if the Great Mosque of the caliph al-Walid, built in 706-714/715. Among ancient cities of the world, Damascus is perhaps the oldest continuously inhabited. Its name, Dimashq in Arabic (colloquially ash-Sham, meaning the northern as located from Arabia), derives from Dimashka, a word of pre-Semitic etymology, suggesting that the beginnings of Damascus go back to a time before recorded history.