Pedro IV of Castille (Chaos)

Pedro IV of the Castilian dynasty was born in 1427 as the son of Pedro III and his wife. After the early death of his father, he became king of Castile and Portugal at the age of only eight years.
When the infamous happened in 1466, many people from Castile-Portugal went there to fight for the pope; although Pedro also sent some troops, he didn't declare war on the , which many sides criticized. The king only succeeded in making the eastern parts of the the new Duchy/Protectorate of the , theoretically still under the pope, de facto under the Duke of Alba (Castile).
1492 (SCNR), a Castilian expedition (well, it was funded by the king, and some of his people are on the ship, but since the Portuguese insisted, the captain and all the sailors were Portuguese - Castilians weren't allowed to build caravels) crossed the Atlantic, made landfall in , claimed it for Castile-Portugal. It is safe to say, however, that the old king didn't participate much on this decision.
In 1497, he died without heirs, and his empire fell to king , forming the .