Philip IV of Spain

Philip inherited the Spanish throne in 1621 at sixteen, also becoming Philip III of Portugal, and immediately plunged into the Thirty Years' War that would drain his kingdoms for decades. He filled his court with painters - Diego Velázquez chief among them - and earned the odd title "Planet King," but his inability to push through domestic or military reform left the empire sprawling and sick. By 1640 Portugal broke away and restored its own monarchy under John IV, collapsing the Iberian Union his grandfather had forged. When he died in September 1665, his young son Charles II inherited the biggest dominion in the world and the mess inside it.