On 11 June 1685, James Scott, Duke of Monmouth, landed on England's west country shore proclaiming liberty and inveighing against the arbitrary rule of his uncle, King James II, who had ascended the throne scarcely four months earlier. On 13 June the invasion was officially known in London and the King's proclamation of that day declared Monmouth and Lord Grey traitors to the nation. Though the government immediately began to contain the rebellion, and the army stopped many from travelling to the west to enlist in the rebel cause, as early as 13 June a small body of recruits arrived from the capital, perhaps in time to hear the dashing, martial, but illegitimate son of Charles II proclaimed “our lawful and rightful sovereign and king by the name of James II.”

Whether Daniel Defoe rode westward with that first contingent of London volunteers, or whether he slipped into Monmouth's camp later that eventful summer, any examination of Defoe's political thought would be rendered less uncertain if we could answer the question that John Robert Moore posed and left unanswered after a half-century's study of his subject's life and writings: “Why had a merchant not quite twenty-five years old left his young wife to follow an adventurer in battle more than a hundred miles away?” Why had this Presbyterian dissenter jeopardized his marriage, career, even life, to enlist under the banner of a self-proclaimed deliverer of parliament, “pro religione et libertate?”