King James II

Roman Catholic. A sincere one too a best as we can tell. Converted after back in England and after getting married to Anne Hyde, the daughter of his brother's prime minister the Earl of Clarendon to his eternal embarrassment.

Inherited the throne easily enough in 1685 but eroded public trust and lost it entirely to King Billy in 1688 of blessed memory.

Paris may have been worth a mass but was England worth less that a rosary? No.