While Charles I and Philip II had strong personalities and were decided to enlarge the empire, their heirs did not follow that style of ruling. Philip III (1578-1621), Philip IV (1605-1665) and Charles II (1661-1700) were more interested in hunting and partying in their palaces. They delegated their functions as kings to their favourites (validos), who turned out to be corrupt.
Philip III delegated in the Duke of Lerma, who decided the expulsion of the Moriscos, Philip IV chose Count-Duke of Olivares as his favourite, and together they tried to reform the administration with the objective of making royal power stronger, and finally the sick and weak Charles II chose his own brother, John of Austria, as his valido. After so many intra-family marriages, poor baby Charles II was born with many physical and mental problems. He died at age 38 in 1700, with no children.
The reign of Philip IV coincided with the Thirty Years War (1618-1648), a complex conflict based on religious issues and balance of power. Spoiler: the Kingdom of France resulted victorious and the Spanish Empire lost its dominance. After 200 years of ruling over the World, the Habsburgs were about to disappear. The Battle of Rocroi (1643) was the first great defeat of the Spanish Army. The Thirty Years War emptied the coffers of the Spanish Empire, and so there were important economic and social crises.
