In Europe, Portugal and Spain remained Catholic and were on the cusp of building global empires. As sponsor of Christopher Columbus' 1492 mission to cross the Atlantic, the Spanish Queen Isabella I (Isabella the Catholic) of Castille was an important figure in the growth of Catholicism as a global religion, for Spain and Portugal followed Columbus' route to establish vast Empires in the Americas. Her marriage to Ferdinand II of Aragon had ensured the unity of the Spanish Kingdom and the royal couple agreed to hold equal authority. Spanish Pope Alexander VI conferred on them the title "Catholic". The "Catholic Encyclopedia" credits Isabella as an extremely able ruler and one who "fostered learning not only in the universities and among the nobles, but also among women". Of Isabella and Ferdinand, it says: "The good government of the Catholic sovereigns brought the prosperity of Spain to its apogee, and inaugurated that country's Golden Age".