 His "Atheomastix; clearing foure truthes, against atheists and infidels" was published posthumously in 1622, a work written against atheism.According to the "Cambridge History of English and American Literature", (1907–21), Volume VII, Fotherby "relied chiefly on St. Thomas Aquinas in his demonstration of the being of God, and maintained that there is a "natural prenotion" that there is a God.