In its early years under the presidency of James Strong, Carleton reflected the theological conservatism of its Minnesota Congregational founders. In 1903, modern religious influences were introduced by William Sallmon, a Yale Divinity School graduate, who was hired as college president. Sallmon was opposed by conservative faculty members and alumni, and left the presidency by 1908. After Sallmon left, the trustees hired Donald J. Cowling, another theologically liberal Yale Divinity School graduate, as his successor. In 1916, under Cowling's leadership, Carleton began an official affiliation with the Minnesota Baptist Convention. It lasted until 1928, when the Baptists severed the relationship as a result of fundamentalist opposition to Carleton's liberalism, including the college's support for teaching evolution. Non-denominational for a number of years, in 1964 Carleton abolished its requirement for weekly attendance at some religious or spiritual meeting.