John II of Portugal

John II became King of Portugal in 1481, though he'd held the throne briefly in 1477. He spent his reign breaking the power of the Portuguese aristocracy and reasserting royal control over a kingdom that had grown unruly. With the nobility subdued, he turned to the ledger and the horizon—reinvigorating Portugal's economy and renewing the push into Africa and Asia that would define the next century of European expansion. He died in 1495, having centralized enough power and momentum that his successors inherited an empire in motion.