Assistant to the Quorum of the Twelve Apostles

Assistant to the Quorum of the Twelve Apostles, commonly shortened to Assistant to the Twelve or Assistant to the Twelve Apostles, was a priesthood calling in The Church of Jesus Christ of Latter-day Saints between 1941 and 1976. As the title of the calling 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. Like counselors in the First Presidency, Assistant to the Twelve was not a distinct priesthood office—rather, it was a calling that any worthy high priest could be asked to fill.

In April 1941, church president Heber J. Grant called five men to serve as Assistants to the Twelve. No more Assistants to the Twelve were called until 1951; the church continued to call Assistants to the Twelve throughout the 1950s, 1960s, and the first half of the 1970s.

Of the 38 men who held the calling of Assistant to the Twelve, thirteen later became members of the Quorum of the Twelve Apostles: Marion G. Romney, George Q. Morris, Hugh B. 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. Additionally, a former Assistant to the Twelve (Alvin R. Dyer) was ordained to the office of apostle without being made a member of the Quorum of the Twelve. 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.

...
Wikipedia