Edessa

Ancient city between the Euphrates and Tigris rivers. It was founded as a military settlement by Seleucus I, one of Alexander the Great's generals.

In the 2nd century BC the city broke away from Seleucid rule and became the capital of the kingdom of Osroëne, which in turn became part of the Roman empire. Roman rule gave way to Byzantine rule, under which Edessa became a Christian archbishopric. Conquered by the Arabs AD 638, it again became Christian in 1098, when Baldwin of Boulogne captured it during the First Crusade and founded the first crusader state, the principality of Edessa. The city was retaken by Muslims 1144.