Turkey's state-run Anadolu Agency said Mesrob Mutafyan, the 84th Armenian Patriarch of Constantinople, died Friday at Istanbul's Armenian Surp Pirgic hospital where he was being cared for. He had been incapacitated since 2008 with an early onset of dementia.
Mesrob was elected Patriarch in 1998, replacing the late Karekin II. He withdrew from his duties in 2008 and Archbishop Aram Atesyan was appointed as the acting patriarch for the Armenian community which numbers an estimated 70,000.
Turkish President Recep Tayyip Erdogan and other Turkish officials called Atesyan to offer their condolences.
Funeral details weren't immediately available.
Preparations for the election of a new patriarch for Turkey were expected to begin after a 40-day mourning period.
Last year, the Turkish government intervened to halt elections at the patriarchate, on the grounds "that the necessary conditions for the electoral process had not been met" and that Mesrob was still alive.