John was a member of the
Kamateros family to which belonged the Empress
Euphrosyne Doukaina Kamatera, wife of
Alexios III Angelos (r. 1195–1203). An educated man, well versed in classical literature, rhetoric and philosophy, he occupied a series of ecclesiastical posts reaching the post of
chartophylax, which he held at the time of his elevation to the patriarchal throne. In 1198–1200, he had an exchange of letters with
Pope Innocent III on the issue of
papal supremacy and the
Filioque clause. He disputed Rome's claim to primacy based on
Saint Peter and asserted that in reality its primacy came from the fact that Rome was the old imperial capital. He intervened in the riots in Constantinople against the arrest of the banker Kalomodios and secured his release, but during the coup of
John Komnenos the Fat on 31 July 1200, he hid in a cupboard as the rebels seized control of the
Hagia Sophia. John X remained in office after Alexios III's deposition in July 1203, and according to Western sources, both he and
Alexios IV Angelos, threatened by the
Fourth Crusade, acknowledged papal supremacy in the same year. After the
capture of
Constantinople during the Fourth Crusade in 1204, he initially fled to
Didymoteichon in
Thrace. In 1206, Emperor of Nicaea
Theodore I Laskaris invited him to
Nicaea, where he had established the
Empire of Nicaea, a Byzantine Greek successor state, but John X refused, perhaps because of his advanced age, and died in May of the same year. The Crusaders then installed a
Latin Patriarchate of Constantinople, while Theodore I Laskaris simply created a new provisional seat of the
Ecumenical Patriarchate of Constantinople in Nicaea, which was eventually restored in Constantinople with the rest of the Empire in 1261. == Notes and references ==