Philip IV (1605-1665) was king of Spain from 1621 to 1665. During his reign Spain was engaged in foreign wars and torn by internal revolt.

Born on April 8, 1605, Philip IV succeeded his father, Philip III, in 1621. He was more intelligent than his father but like him allowed his government to be run by minister-favorites. Philip's principal minister, Gaspar de Guzmán, Count of Olivares, dominated his councils and was the effective ruler of Spain for more than 20 years. In 1627 the ruinous expenses of Spain's involvement in the Thirty Years War forced the government to declare itself bankrupt; the war effort continued, however, and the Mantuan campaign (1628-1631) led to an open conflict with France, which became intensified in 1635.

Spanish troops at first came close to Paris, but the situation rapidly deteriorated. Olivares's desperate attempts to raise funds for the prosecution of the war provoked dissent and rebellion, and in...