Philip IV, 1605–65, king of Spain, Naples, and Sicily (1621–65) and, as Philip III, king of Portugal (1621–40); son and successor of Philip III of Spain. Philip IV was intelligent but lacked interest in the affairs of state, which were handled (until 1643) by the conde de Olivares. During his reign, Spain continued to decline politically and economically. Spanish involvement in the Thirty Years War increased as war was resumed (1621) in the Netherlands and fighting started (1622) with France over the Valtellina question. The war with France continued after the Peace of Westphalia (1648), became complicated by Spanish intervention in the French Fronde, and ended (1659) with the humiliation of Spain (see Pyrenees, Peace of the). The war gave Portugal the opportunity to revolt (1640). Catalonia also rose and was long occupied by the French. Spain had to recognize the independence of the United Provinces of the Netherlands at the Peace of Westphalia and lost Roussillon and part of the Spanish Netherlands to France at the Peace of the Pyrenees. Philip's daughter, Marie Thérèse, was married to Louis XIV of France. Thanks to the presence of Velázquez at his court, Philip was probably one of the most frequently portrayed monarchs in history. He was also a patron of Rubens and Cano and was largely responsible for building up the royal collection of paintings, which later became the basis of the Prado Museum. Calderón de la Barca and Tirso de Molina continued the great tradition of Spanish drama during his reign. Philip was succeeded by his son, Charles II.