It was, from the start, a dangerous experiment. Charles I of England was a Protestant, the fifteen-year-old French princess a Catholic. The marriage was arranged for political purposes, and it seemed a mismatch of personalities. But against the odds, the reserved king and his naively vivacious bride fell passionately in love, and for ten years England enjoyed an era of peace and prosperity.

When Charles became involved in war with Puritan Scotland, popular hatred of Henrietta’s Catholicism roused Parliament to fury. As the opposition party embraced new values of liberty and republicanism—the blueprint for the American War of Independence and the French Revolution—Charles’s fears for his wife’s safety drove him into a civil war that would cost him his crown and his head.

Rejecting centuries of hostile historical tradition, prize-winning biographer Katie Whitaker uses a host of original sources—including many unpublished manuscripts and letters—to create an intimate portrait of a remarkable marriage.