Charles II is restored to the English throne, and his court is lively and even scandalous. The country is eager for succession to be clear and certain: The next king will be the son of Charles II and his queen, Catherine of Braganza. Yet Catherine, daughter of the king of Portugal and a Catholic, has never been popular with the English people. She is also having great difficulty conceiving an heir, even as many of Charles's well-known mistresses are...