The leader of the Greek Orthodox Church in Chicago died suddenly Friday evening of an unexpected illness.

Metropolitan Iakovos of Chicago, 89, died following surgery at Weiss Memorial Hospital, according to spokesman John Ackerman. Metropolitan Iakovos had served the church for almost 50 years, 38 of those years in Chicago. The Metropolis of Chicago consists of 34 parishes in Illinois and another 25 in Wisconsin, Minnesota, Iowa, Missouri and northern Indiana.

He had been elected and enthroned as Bishop of Chicago in 1979. He remained active in his ministry until his death.

“Under his 38-year tenure, the ministries of the Greek Orthodox Church increased greatly through several initiatives, especially in philanthropy and the area of social justice,” the church said in the statement.

Archbishop Demetrios of America in consultation with the Eparchial Synod named Metropolitan Nicholas of Detroit as the temporary substitute until a successor is named.

Born Michael Garmatis in Athens, Greece, in 1928, Metropolitan Iakovos later moved as a younger clergyman to Boston where he earned his doctorate from Boston University and taught at the Holy Cross Greek Orthodox School of Theology.

Under Metropolitan Iakovos’ leadership, the church increased its efforts to assist the homeless and those in need. He founded new youth programs, established various local dialogue commissions with other faith communities, and worked with other area religious leaders in promoting justice and truth.

“A long friendship connected me with the departed hierarch since the time we were both students at the School of Theology of the University of Athens following World War II,” Archbishop Demetrios said in a statement. “Already at that time, the unforgettable hierarch distinguished himself for his deep piety, his ecclesiastical ethos and the special love he had for the sacred services of our Orthodox liturgical tradition.”

Archbishop Demetrios will preside at the funeral, which will be held 10:30 a.m. June 9 at the Greek Orthodox Cathedral of the Annunciation of the Virgin Mary. The divine liturgy will precede the funeral at 7:30 a.m. The archbishop will chant a Trisagion service in the cathedral at 7 p.m. June 8.