: In this paper, the author will demarcate three main stages of the development of Étienne Gilson’s doctrine on Christian philosophy through an examination of some of Gilson’s key works, treated in chronological order. Thus, he proceeds to explicate how Gilson’s doctrine developed from its gestational stage in the 1920s through the first Christian philosophy debate of the 1930s, into its 2nd stage of birth and infancy from the 1930s through the early 1950s, ending with the 3rd stage of maturity (...) in the later 1950s and 1960s. Furthermore, he notes that implicit throughout those three stages are notions of Christian philosophy as existing in two modes: one as the philosophical component present within theology and the second properly speaking outside of theology though by no means outside of the influence of Christianity. Additionally, Gilson’s influence upon St. John Paul II’s treatment of Christian philosophy in Fides et Ratio is addressed. The paper culminates in showing how Gilson’s mature doctrine on Christian philosophy is relevant as a guide for doing Christian philosophy in this Third Christian Millennium. (shrink)