The Siege of Sinope in 1214 was a successful siege and capture of Sinope by the Seljuq Turks under their Sultan, Kaykaus I (r. 1211–1220). Sinope was an important port city on the Black Sea coast of modern Turkey, at the time held by the Empire of Trebizond, one of the Byzantine Greek successor states formed after the Fourth Crusade. The siege is described in some detail by the near-contemporary Seljuq chronicler Ibn Bibi. The Trapezuntine emperor Alexios I (r.