turn of the 20th century (1890s–1930s)

The Fundamentalist–Modernist controversy in the US; the Niagara Bible Conference

By the late 19th century, historical criticism of the Bible and attempts to reconcile faith with Darwinism had penetrated American Protestantism. Defenders of the traditional "fundamentals" of the faith came to be called fundamentalists.

John Nelson Darby's dispensationalist ideas combined with Princeton's doctrine of biblical inerrancy. This led to the formulation of five "fundamentals" at the Niagara Bible Conference (1895): the inerrancy of Scripture, the virgin birth of Jesus, his substitutionary death, his bodily resurrection, and his imminent return.

Fundamentalism drew strength from revivalism. At times it allied with confessionalists, as when the Presbyterian General Assembly adopted the "fundamentals." But the seminaries of all the major denominations came under modernist control. After that, many conservatives left them and founded their own churches, Bible colleges, and seminaries. Fundamentalism withdrew into its own separatist "ghetto."