While you came here, please see my friend's photos about Rusafa, which some of them uniquely pictured.
Resafa (Arabic: الرصافة), known in Roman times as Sergiopolis, was a city in Syria. It is an archaeological site situated south-west of the city of Ar Raqqah and the Euphrates.
The site dates back to the 9th century B.C, when a military camp was built by the Assyrians. During Roman times it was a desert outpost fortified to defend against the Sassanids. It flourished as its location on the caravan routes linking Aleppo, Dura Europos, and Palmyra was ideal. Resafa had no spring or running water, so it depended on large cisterns to capture the winter and spring rains. Fortunately, the rainfall in the area was more than sufficient. Resafa was planted right in the path of the Persian-Byzantine wars, and was therefore a well-defended city that had massive walls that surrounded it without a break. It also had a fortress.
The city's naming comes from "Sergius",a Roman soldier who was persecuted for his Christian faith. Sergius was brought to Resafa for his execution, and there he became a martyr for the city. A church was built to mark his grave and the city was renamed Sergiopolis.
Info taken from Wikepedia.org