sentences:  On June 16, 1956, Hannan was named titular bishop of Hieropolis and auxiliary bishop of Washington, and was consecrated in the Cathedral of St. Matthew the Apostle on August 28.As Auxiliary Bishop of Washington, Hannan was part of the U.S. delegation to the Second Vatican Council, where he served as a press officer.Until his death in 2011, Hannan was one of two living United States bishops to have attended all four sessions of Vatican II, along with Raymond Hunthausen, Archbishop Emeritus of Seattle, Washington.