Citharizum is a Catholic titular see. The original diocese lay in Roman Armenia; the city was situated in Asthianene or Balabitene, a region between Masius and Anti-Taurus, north of Commagene and Mesopotamia. It is identified with the modern Keterig.
Justinian built a castle there, in which he stationed a garrison under the command of a duke. He also included it in the province, Armenia Quarta, which he had just formed. In 613 Citharizum was taken by Ashot, a general of the Persian king, Chosroes II.
In the records of the Trullan Council (692) we meet the name of Marianus, Bishop of Kitharizon (or Kithariza), for the name seems to have been indeclinable (Lequien, I, 453). No other bishop is known. the city is mentioned in Parthey, Notitia Prima, about 840 as belonging to Armenia Quarta, under the metropolis of Melitene.