Luxemburg, Duchy of / Philippe IV (Duke Philip IV), King of Spain

Philip IV of Spain (Spanish: Felipe IV) was King of Spain (as Philip IV in Castille and Philip III in Aragon) and Portugal as Philip III (Portuguese: Filipe III). He ascended the thrones in 1621 and reigned in Spain until his death and in Portugal until 1640. Philip is remembered for his patronage of the arts, including such artists as Diego Velázquez, and his rule over Spain during the challenging period of the Thirty Years' War.

On the eve of his death in 1665, the Spanish Empire had reached approximately 12.2 million square kilometers (4.7 million square miles) in area but in other respects was in decline, a process to which Philip contributed with his inability to achieve successful domestic and military reform.