Mopsuestia (Greek Μοψουεστία, also transliterated as Mopsouhestia or Mompsuestia) or Mopsus or Mamistra is an ancient city of Cilicia Campestris (later Cilicia Secunda) on the Pyramus (also Pyramos, now the Ceyhan Nehri) river located approximately 20 km east of present-day Adana (then called Antiochia in Cilicia) in Adana Province, Turkey.
The founding of this city is attributed to the soothsayer, Mopsus, who lived before the Trojan war, although it is scarcely mentioned before the Christian era. Pliny the Elder calls it the free city of Mopsos (Hist. nat., V, 22), but the ordinary name is Mopsuestia, as found in Stephanus of Byzantium and all the Christian geographers and chroniclers. Under the Seleucid Empire, the city took the name of Seleucia on the Pyramus (Greek: Σελεύκεια προς τον Πύραμο, also transliterated Seleucia pros ton Pyramo, Seleukheia pros ton Pyramo, Seleukeia pros ton Pyramo, and Seleuceia pros ton Pyramo; Latin: Seleucia ad Pyramum), but gave it up at the time of the Roman conquest; under Hadrian it was called Hadriana, under Decius Decia, etc., as we know from the inscriptions and the coins of the city. Constantius II built there a magnificent bridge over the Pyramus (Malalas, Chronographia, XIII; P.G., XCVII, 488) afterwards restored by Justinian (Procopius, De Edificiis, V. 5) and still to be seen in a very bad state of preservation.
Christianity seems to have been introduced very early into Mopsuestia and during the 3rd century there is mention of a bishop, Theodorus, the adversary of Paul of Samosata. Other famous residents of the early Christian period in the city’s history include Saint Auxentius (d. 360), and Theodore, bishop from 392–428, the teacher of Nestorius. The city was taken by the Arabs at the very beginning of Islam; in 686 all the surrounding forts were occupied by them and in 700 they fortified the city itself (Theophanes, "Chronogr.", A. M. 6178, 6193). Nevertheless because of its position on the frontier, the city was recaptured from time to time by the Byzantines. The war between Muslims and Byzantines was ongoing and was besieged in vain by the Byzantine troops of John I Tzimisces in 964. The city was taken the following year after a long and difficult siege by Nicephorus Phocas.
Mopsuestia then numbered 200,000 inhabitants, some of whom were Muslim, and the Byzantines made efforts to re-Christianize the city. Its river, the Pyramus, formed a great harbour extending twelve miles to the sea. In 1097 the Crusaders took possession of the city and engaged in a fratricidal war under its walls; it remained in the possession of Tancred who annexed it to the Principality of Antioch. It suffered much from internecine war between Crusaders, Armenians, and Greeks who lost it and recaptured it alternately notably in 1106, in 1152, and in 1171. The Greeks finally abandoned it to the Armenians. Set on fire in 1266, Mamistra, as it was called in the Middle Ages, became two years afterwards the capital of the Armenian Kingdom of Cilicia, at the time that a council was held there. Although it was by this time in a state of decline it still possessed at least four Armenian churches, and the Greek diocese still existed at the beginning of the fourteenth century (Le Quien, Oriens Christianus, II, 1002 ). In 1322, the Armenians suffered a great defeat under its walls. In 1432 the Frenchman Bertrandon found the city occupied by the Muslims and largely destroyed. Since then it has steadily declined and became, under the Turkish name of Misis, a little village. Misis was renamed as Yakapınar in 1960s.