Circesium (KERKESION, KERKISION, KIRKISIA, CERCUSIUM, CIRCESSUS), a titular see of Osrhoene. Founded under Diocletian and restored by Justinian, it is now identified with the village Abu Serai, on the left bank of the Euphrates, at the confluence of the Khabur, where the river was commonly crossed. The ancient city, however, had replaced a still older one, called Sirhi in Assyrian texts. Benjamin of Tudela and many after him identified it wrongly with Kharkamis (Carchamish), one of the capitals of the Hittites, situated at Jirbas, or Jerablus, the present name of Europos, or Oropos. Circesium was a bishopric in Osrhoene, suffragan of Edessa; it figures only in Parthey’s “Notitiae episcopatuum” (c. 840). Lequien (II, 977) mentions five bishops: Jonas, who was present at Nicaea, and had suffered mutilation during the preceding persecution; Abramius, present at Chalcedon; Nonnus, a Severian (518 and 532); Davides, present at Constantinople (536); Thomas (553). There are also records of fourteen Jacobite bishops, from 793 to 1042.