He was the Catholicos of All Armenians of the Armenian Apostolic Church at the Mother See of Holy Etchmiadzin in 1908–1910. He succeeded Mkrtich I Khrimian (better known as Khrimian Hayrik), who reigned as Catholicos from 1892 to 1907.
Informations available here: https://en.wikipedia.org/wiki/Matthew_II_Izmirlian