King Charles I was a Protestant. Henrietta Maria, a 15-year-old French princess, was a Catholic. Arranged for political gain, their marriage was a dangerous experiment, yet against the odds they fell in love. However Henrietta's Catholicism fuelled rumours of improper influence over a supposedly helpless king. Unable to trust his Parliament, Charles's fear for the queen's safety plummeted the country into civil war and forced her to flee abroad, never to see her husband again. They kept up a poignant correspondence but in 1649, the king was condemned as a traitor and publicly executed, thus ending an extraordinary partnership that influenced the course of history.