John V of Constantinople was a 7th-century Eastern Orthodox prelate who served as the Ecumenical Patriarch of Constantinople from 669 until his death in 675. His leadership occurred during a period of significant conflict for the Byzantine Empire, as the first major siege of the city by the Umayyad Caliphate began during his tenure. He succeeded Thomas II and was followed in his office by Constantine I.
Life and tenure
During his time as patriarch, the city faced the intense first siege conducted by the Umayyad Caliphate between 674 and 678. Although the conflict continued after his passing, his reign was defined by this period of military pressure on the Byzantine capital. He held his position for approximately six years before his death in August 675.
Veneration
As a recognized hierarch of the church, he is commemorated as a saint within the Catholic and Orthodox traditions. His legacy is preserved through the historical continuity of the Ecumenical Patriarchate, following the lineage of leaders who managed the religious affairs of Constantinople during the early medieval period.