As the title suggests, men who held this position assisted the Quorum of the Twelve Apostles in fulfilling their priesthood responsibilities.
Assistants to the Twelve were general authorities and were generally assigned by the Twelve Apostles to preside over and speak at stake conferences; re-organize stakes; tour missions; and assist in the direction of worldwide missionary work.
Brown, Gordon B. Hinckley, N. Eldon Tanner, Boyd K. Packer, Marvin J. Ashton, L. Tom Perry, David B. Haight, James E. Faust, Neal A. Maxwell, Robert D. Hales, and Joseph B. Wirthlin.
Seven Assistants to the Twelve (Romney, Brown, Dyer, Isaacson, Hinckley, Tanner, and Faust) later served in the church's First Presidency, with one (Hinckley) later becoming the church's president.
In 1976, church president Spencer W. Kimball announced that the calling of Assistant to the Twelve would be discontinued.