In 1563, Louis reconquered Angoulême and Cognac. In 1569, he participated in the Battle of Jarnac, was named governor of Brittany and married, on February 4, 1570, Catherine de Lorraine (1552-1596), sister of Henry I, Duke of Guise and of Charles of Lorraine, Duke of Mayenne. He approved of the St. Bartholomew's Day massacre, and fought the Protestants again in 1575 in Poitou.