Widmer states that it was primarily through "the post 1883 sermons of Latter-day Saint Apostle George Q. Cannon that the modern interpretation and significance of the First Vision in Mormonism began to take shape." As the sympathetic but non-Mormon historian Jan Shipps has written, "When the first generation of leadership died off, leaving the community to be guided mainly by men who had not known Joseph, the First Vision emerged as a symbol that could keep the slain Mormon leader at center stage." The centennial anniversary of the vision in 1920 "was a far cry from the almost total lack of reference to it just fifty years before." By 1939, even George D. Pyper, the Church's Sunday School superintendent and manager of the Mormon Tabernacle Choir, found it "surprising that none of the first song writers wrote intimately of the first vision."