The union of the Spanish Kingdoms of Aragon and Castile was effected in 1469 by Ferdinand’s marriage to his cousin Isabella I, Queen of Castile. Ferdinand had hoped by this alliance to obtain the Castilian crown for himself, but his high-spirited and politically astute wife firmly retained sovereign authority in her own realm.
The political philosophies of the two rulers were almost identical, however, and their reign was inaugurated with the promulgation of energetic and sweeping measures designed to strengthen the royal authority and to curb the power of the nobles, who had usurped many privileges and functions of the crown. In 1478 a bill issued by Pope Sixtus IV empowered the king and queen to appoint three inquisitors to deal with heretics and other offenders against the church; this marked the beginning of the Spanish Inquisition.
The year 1492 was the most notable of Ferdinand’s reign. It opened with the conquest of the province of Granada, which marked the victorious conclusion of the long struggle against the moors. In August Christopher Columbus, sponsored by Ferdinand and Isabella, set sail from the small Spanish seaport of Palos on his epoch-making voyage to America, which was the first step in the creation of the Spanish overseas colonial empire.