Matthew I was born in 1845 in Istanbul as Simeon Martirosi Izmirlian (Սիմէոն Մարտիրոսի Իզմիրլեան).

He was elected in 1872 as secretary of the Armenian religious council of Constantinople,[1] and raised to level of "dzayrakouyn vardapet" or supreme archimandrite in 1873 and bishop in 1876.

[1] He returned briefly from exile in 1908 after the Committee of Union and Progress declared the restoration of the constitution in 1908 and was reelected as Patriarch of Constantinople for a few months.

During his tenure, he became the first Catholicos to make a pilgrimage to Ani, the ruined capital of medieval Armenia.

[2] He was also a prolific author and published extensively, including a voluminous book in 1881 on the history of the Armenian Apostolic Church and the Catholicosates of Sis and Aghtamar.