Political map of North America & the Caribbean 29 September 1513 (Balboa reaches the Pacific): Encouraged by Spanish successes on the Isthmus of Panama (1510), King Ferdinand II (Ferdinand II of Aragon) created the Governorate of Castilla de Oro to administer the region in 1513. While establishing Spanish rule, Vasco Núñez de Balboa learned from a local chief that a vast “South Sea” lay beyond Panama’s mountains—and a gold-rich empire (the Incas (Inca Empire)) lay beyond that. Balboa eagerly headed south to confirm these claims, reaching the Pacific Ocean in late September.