(OSV News) -- On May 17, 1846, the U.S. bishops, 23 in number, consecrated the United States of America to the patronage of the Blessed Mother under the title of the Immaculate Conception. The story behind this action, the story of the Immaculate Conception evolving as a dogma of the Church, was 14 centuries in the making. It began during the ecumenical council held at Ephesus (Turkey) in 431, where the Church Fathers proclaimed that Mary was the Mother of God.