Who was the most famous absolute monarch from Spain?

The most famous absolute monarch from Spain was King Philip II, who reigned from 1556 to 1598. He is known for his extensive empire, which included territories in Europe, the Americas, and Asia, and for his staunch defense of Catholicism during the Protestant Reformation. Philip II's centralized rule and ambitious military campaigns, including the ill-fated Spanish Armada, significantly shaped Spain's history and influence during the 16th century. His reign is often seen as the height of Spanish power and cultural achievement.