the Sunday School developed a unified 8-year-cycle of covering the LDS Church's scriptures in its curriculum. There was also a shift from having members of the Sunday School general board do all the training for new teachers to providing materials which developed into the book Teaching: No Greater Call. The hymn practice time in Sunday School was also renamed to worship through music. Nelson later served for four and a half years as a regional representative. For approximately half of this time, he was assigned to oversee the fourteen stakes at BYU, while he worked with the stakes in Kearns, Utah, for the rest of his tenure. Apostle Nelson was called as an apostle by church president Spencer W. Kimball, to whom he had served as a personal physician for many years. Nelson was sustained as a member of the Quorum of the Twelve Apostles on April 7, 1984, during the church's general conference. He was ordained an apostle on April 12, 1984, by Gordon B. Hinckley. At the same conference, Dallin H. Oaks was sustained as a member of the Quorum of the Twelve. Nelson and Oaks filled the vacancies in the Quorum created by the deaths of LeGrand Richards and Mark E. Petersen. Early in his service as an apostle, Nelson was an adviser to the church's Young Women organization and was supportive of the developing of the Young Women values and Personal Progress program. In 1991, Nelson served as the negotiator for the LDS Church with the Internal Revenue Service over whether contributions to support missionaries serving would be tax deductible. In 1992, it was identified he was on the Strengthening Church Members Committee, alongside fellow apostle James E. Faust. In 1993, he was the church's lead delegate to the Parliament on World Religions. For a time he was also the church's representative to a US State Department committee on international religious freedom. Nelson's assignments as an apostle have included supervisory responsibility for the LDS Church in Africa. In 2009, he, along with his wife and others, were attacked while in Mozambique. He also made several other visits to that continent, including one to Kenya in 2011. From 2007 to 2015, Nelson was as a member of the Church Boards of Trustees/Education, the governing body of the Church Educational System, and the chairman of its executive committee. He was succeeded as chairman of the executive committee by