(and matriarchs.) After the Islamic conquest in the 7th century CE the region was known by the name of an Arab tribe Diyar Mudar, the land of the Mudar. In 762, the Caliph al-Mansur built a garrison city at the junction of the Euphrates, Ar-Rafiqa, which merged with the Hellenistic city Kallinikos into the urban agglomeration Raqqa. Archaeological research in the Balikh River basin European travellers of the 19th century noted the presence of archaeological remains in the Balikh Valley, but the first investigations were not carried out until 1938, when the English archaeologist Sir Max Mallowan (husband of author Agatha Christie) spent six weeks investigating five archaeological sites dating from the seventh to the second millennium BCE. In 1969, a French team directed by Jacques Cauvin started their investigations, his team exposed eight neolithic occupation levels in a limited sounding on the northern slope of the site. Excavations at Tell Hammam al-Turkman were initiated under the direction of dr Maurits N. van Loon (1981–1986, University of Amsterdam). As per 1988, the project was continued under the direction of dr Diederik J.W. Meijer (1988–2001, Leiden University). The site provided a well-stratified material culture that allowed analysis of the settlement history of the Balikh valley. Later other excavations have complemented the reconstruction of a regional occupation history. One of the oldest sites, Tell Sabi Abyad, is currently being excavated under the leadership of Dutch archaeologist Peter Akkermans. Incidentally, the Turkish archaeological site of Göbekli Tepe is located on a hill directly north of and overlooking the Harran Plains that feed the Balikh river system. Excavated archaeological sites in the Balikh River basin Tell Aswad Tell Bi'a (near the confluence of the Balikh with the Euphrates) Tell Balabra (on the Wadi Qaramogh) Tell Chuera (Assyrian Harbe; on the Wadi Chuera) Tell Hammam et-Turkman Tell Jidle Tell Sabi Abyad Tell Sahlan Tell as-Saman Tell Zeidan (near Raqqa Syria) References External links Tell Sabi Abyad archaeological project Rivers of Turkey Rivers of Syria International rivers of Asia Euphrates Landforms of Şanlıurfa Province