Barbalissos, a titular see of Mesopotamia. It was a city in Provincia Augusta Euphratensis, where the Equites Dalmatae Illyriciani kept garrison (Notit. Dignitat. Orientis, ed. Boecking, 88, 389). Justinian raised anew its walls (Procop., De adific., II, 19; Malalas, Chronograph., XVIII, in Migne, P.G., XCVII, 676). At an early date it was a suffragan of Hierapolis, a metropolis in the Patriarchate of Antioch. Its bishop Antonius was present at the Council of Niciva (325); two other bishops, Aquilinus and Marinianus, are known between 431 and 451 (Lequien, II, 949). The see is still mentioned in the sixth century. From 793 to 1042 five Jacobite bishops are known bearing this title (Revue de l’Orient chrétien, VI, 192). Its site is marked by the ruins at Qala’ at Balis, which partly retains the old name, south of Meskene, on the road from Aleppo to Soura, where the Euphrates turns suddenly to the east. The spellings Barbarissos and Barbairissos in later “Notitiae” are wrong; so is Barbaricus campus in Procopius (De hello Persico, II, 99). Lequien (I, 407) wrongly gives Barbalissus as synonymous with Balbisse, another bishopric in Cappadocia, known only in 1143.