J. Gresham Machen (1881-1937) was the principal figure in the founding of the OPC if for no other reason than that the Presbyterian controversy in which he played a crucial role provided the backdrop for the denomination begun in 1936. A distinguished New Testament scholar at Princeton Seminary from 1906 to 1929, Machen defended the historical reliability of the Bible in such works as The Origin of Paul’s Religion (1921) and The Virgin Birth of Christ (1930). He emerged as the chief spokesman for Presbyterian conservatives by issuing a devastating critique of Protestant modernism in the popular books Christianity and Liberalism (1923) and What is Faith? (1925). When the northern Presbyterian church (PCUSA) rejected his arguments during the mid-1920s and decided to reorganize Princeton Seminary to create a moderate school, Machen took the lead in founding Westminster Seminary in Philadelphia (1929) where he taught New Testament until his death. His continued opposition during the 1930s to liberalism in his denomination’s foreign missions agencies led to the creation of a new organization, The Independent Board for Presbyterian Foreign Missions (1933). The trial, conviction and suspension from the ministry of Independent Board members, including Machen, in 1935 and 1936 provided the rationale for the formation in 1936 of the OPC. Only six months after the new denomination’s beginning, Machen died in Bismarck, North Dakota while trying to rally support for the OPC. He was arguably the most important conservative Protestant thinker of the first half of the twentieth century and the guiding light for the first generation of Orthodox Presbyterians.