...James III would never regain the throne, and after the death of Louis XIV could no longer remain in France at St. Germain-en-Laye. He married, had two sons, lived in Rome as a guest of the Pope, and died on January 1, 1766.
Although his claim to succeed his half-sister Anne (who would succeed William III) was secure, Parliament had passed the Act of Succession in June of 1701, preventing any Catholic to become monarch or be married to a monarch. At his birth, of course, there had been rumors that he was not really the son of James II and Mary Beatrice of Modena, but his great likeness to his father and mother as he grew up put the lie to that. Winston Churchill commented that if James Francis Edward had renounced his Catholicism in 1714, the Tory party would have backed his 1715 invasion and he might have reigned... More...
Read about The Princess Escapes and how the old pretender got married.