Anglo-French War of 1557–1559 and Loss of Calais

England entered the renewed Habsburg-Valois conflict in 1557 as an ally of Philip II of Spain, Mary I’s husband. English forces participated in the successful campaign around Saint-Quentin, but the war imposed new demands for money, troops and supplies upon a government already facing religious and dynastic strain.

In January 1558, French forces captured Calais, ending more than two centuries of English possession. The loss carried military, financial and symbolic importance and became closely associated with the final year of Mary’s reign. The wider conflict ended with the treaties of Cateau-Cambrésis in April 1559.

A Queen’s Assassin places the Fitzwarrens’ return from Europe beside Philip’s departure and the failing health of Mary I. The war provides the external pressure against which the novel’s contests over succession, money and the Knights of St John unfold.