John X Camaterus was the Patriarch of Constantinople from 1198 to 1206. He fled to Thrace with the deposed emperor Alexius V after the capture of Constantinople during the Fourth Crusade in 1204. In 1206 Theodore I Lascaris invited him to Nicaea where Theodore founded the Byzantine successor state of the Empire of Nicaea, but John died in the same year. The Crusaders installed a Latin Patriarch in Constantinople, while Theodore simply created a new Greek Patriarchate in Nicaea, which was eventually restored in Constantinople with the rest of the Empire in 1261.