Ferdinand II of Aragon

Ferdinand inherited Aragon and its Mediterranean holdings in 1479 - kingdoms stretching from Catalonia to Sicily. His marriage to Isabella of Castile five years earlier became the cornerstone of what would be called Spain, though the two realms stayed legally separate for another two centuries. In 1492 they took Granada, ending the Reconquista, and sent Columbus west. After Isabella died in 1504, their daughter Joanna inherited Castile but was deemed unstable; Ferdinand made himself regent in 1507. He remarried, conquered Naples, then seized most of Navarre in 1512. When he died in 1516 he ruled every territory that would become modern Spain, but power passed quickly to his grandson Charles.