CTESIPHON , in ancient times a city on the west bank of the Tigris, opposite the Hellenistic city of Seleucia, 25 mi. (40 km.) S.E. of modern Baghdad. Though greatly influenced by its Hellenistic origins Ctesiphon was basically a Persian city. A large Jewish community resided there and the town also served as a commercial center for the Jews of the surrounding area. When the Jews of Seleucia were persecuted about 41 b.c.e., they were able to take refuge in Ctesiphon (Jos., Ant., 18:374ff.) and when the city was taken by Carus in 283 c.e., it was found to have a large Jewish community (T. Noeldeke (tr. and ed.), Geschichte der Perser und Araber… des Tabari (1879), 49, n. 1). The Talmud (Yoma 10a) identifies Ctesiphon with the biblical Resen and the Targum Pseudo-Jonathan equates the city with Calneh (Gen. 10:10, 12). The amoraim*Ḥiyya b. Abba and Rabba b. Ḥiyya resided in Ctesiphon, both being termed "Ketosefa'ah" ("resident of Ctesiphon," Beẓah 38b; Yev. 104a; bb 93b). For commercial and legal purposes Ctesiphon was considered as a part of Bet-Ardeshir which controlled the other bank of the Tigris. This is illustrated by the fact that the inhabitants of Bet-Ardeshir were authorized to certify the signatures on bills of divorce from Ctesiphon, but not vice versa. For purpose of *eruv teḥumin the two cities were considered one, and carrying between them was permitted (Eruv. 57b). The Arab conquest of Ctesiphon (637 c.e.) ended the city's growth, and the founding of Baghdad (762) brought about its total ruin.
M. Streck, Seleucia und Ktesiphon (1917); O. Reuther, Die Ausgrabungen… Ktesiphon-Expedition, Winter 1928–1929 (1930); J. Obermeyer, Landschaft Babylonien (1929), 351, index s.v.Ktesiphon.
Ctesiphon (tĕs´Ĭfŏn´, tē´sĬ–), ruined ancient city, 20 mi (32 km) SE of Baghdad, Iraq, on the left bank of the Tigris opposite Seleucia and at the mouth of the Diyala River. After 129 BC it was the winter residence of the Parthian kings. Ctesiphon grew rapidly and was of renowned splendor. The Romans captured it in warring against Parthia. It became the capital of the Sassanids in c.224 and a center of Nestorian Christianity. In 637 it was taken and plundered by the Arabs who renamed it, along with Seleucia, al Madain; it was abandoned by them when Baghdad became the capital of the Abbasids. It is now a suburban part of Baghdad. The ruined vault of the great audience hall contains the world's largest single span of brickwork.