Sylvester William Treinen

Styles of Sylvester William Treinen

Reference style	The Most Reverend
Spoken style	Your Excellency
Religious style	Monsignor

Sylvester William Treinen (November 19, 1917 – September 30, 1996) was an American prelate of the Roman Catholic Church. He served as Bishop of Boise from 1962 to 1988.

Sylvester Treinen was born in Donnelly, Minnesota, to William John and Kathryn (née Krausen) Treinen. He attended Crosier Seminary in Onamia from 1935 to 1941, and earned a Bachelor of Arts degree from St. Paul Seminary in Saint Paul in 1943. He was ordained to the priesthood on June 11, 1946.

As a priest of the Diocese of Bismarck in North Dakota, Treinen was a curate in Dickinson from 1946 to 1950, and secretary to Bishop Vincent James Ryan and his successor, Bishop Lambert Anthony Hoch, from 1950 to 1953. He then served as a curate at the Cathedral of the Holy Spirit (1950–57), chancellor of the diocese (1953–59), and curate at St. Anne's Church in Bismarck (1957–59). From 1959 to 1962, he was pastor of St. Joseph's Church in Mandan.