In 1521, Emperor Charles V added the city to his possessions in the Low Countries, leading to a period of religious strife and economic decline. During the 16th century, Tournai was a bulwark of Calvinism, but eventually it was conquered by the Spanish governor of the Low Countries, the Duke of Parma, following a prolonged siege in 1581. After the fall of the city, its Protestant inhabitants were given one year to sell their possessions and emigrate, a policy that was at the time considered relatively humane, since very often religious opponents were simply massacred.