France
Charles VIII, 1483-1498
After the legendary spider king, we get the knight-errant. Charles VIII was a hopeless romantic, raised on stories of Charlemagne, to which the Renaissance now added tales of the heroes of Greece and Rome. He believed he was destined for great things, though he had only an ordinary competence.
When he took power, the nobles again rose in rebellion, less against the young king himself than in a squabble over who would advise him. In 1484 and again in 1485 royalist forces defeated rebel forces, demonstrating decisively that the French crown finally had an army capable of holding its own that was not controlled by the nobility.
In the late 1480s, royal forces crushed the army of Brittany, up to now still essentially an independent nation. In late December 1491, Anne of Brittany married Charles, bringing the war and Breton independence to an end.
With the home front relatively secure, Charles reconciled with one of the chief rebels, Louis of Orleans, and tried to unite the nobility in the cause of a foreign war. Charles made himself heir to the ancient Angevin claim to Naples, gathered a large army around him, and proceeded to invade Italy in 1494. The consequences for France were negligible, though the consequences for northern Italy were major. Hardly had the king returned to France, though, than he died, in 1498. His successor was the same Louis of Orleans, whom Charles had pardoned. Louis XII really belongs to the next century, though, so our narrative ends here.