To my daughters I can say, "Your Grandfather Brown was a Theist."
His beliefs were strongly influenced by The Fundamentals. The Fundamentals: A Testimony To The Truth (generally referred to simply as The Fundamentals) is a set of 90 essays published from 1910 to 1915 by the Bible Institute of Los Angeles. The Fundamentals were edited by A. C. Dixon and later by Reuben Archer Torrey. The Fundamentals was first published as a 12-volume set, and later as a four-volume set retaining all 90 essays. The 90 essays were written by 64 different authors, representing most of the major Protestant Christian denominations.
The essays were written to affirm conservative Protestant beliefs, especially those of the Reformed tradition, and defend against ideas deemed inimical to them. They are widely considered to be the foundation of modern Christian fundamentalism.
The project was initially conceived in 1909 by California businessman Lyman Stewart and his brother Milton. They anonymously provided funds for collecting essays to set out what they believed to be the fundamentals of Christian faith, and for printing and distributing copies of the collected essays. The Fundamentals was sent free to ministers, missionaries, professors of theology, YMCA and YWCA secretaries, Sunday School superintendents, and other Protestant religious workers in every English-speaking country. Over three million volumes (250,000 sets) were sent out.
The volumes defended orthodox Protestant beliefs and attacked higher criticism, liberal theology, Catholicism (also called Romanism by them), socialism, Modernism, atheism, Christian Science, Mormonism, Millennial Dawn, Spiritualism, and evolutionism.