Ferdinand and Isabella of Spain otherwise known as the Catholic Monarchs are giants of Spanish history. In 1492 they completed the reconquista defeating the Cordoba of Granada exterminating the last Muslim state in the Iberian peninsula.
Shortly after on March 31st 1492 they decreed the Edict of Expulsion forcing all Jews and Muslims to either convert or leave Spain in 6 months. 
During this time they would also began the Spanish Inquisition to stomp out heresy and confirm the conversion of all Converso and Morisco to Catholicism.
Also in 1492 the Catholic Monarchs sponsored Christopher Columbus expedition to India (side note: no one thought the world was flat or a square people knew the world was round they just thought it was a lot larger than it actually was and you'd die before you'd reach India. Columbus thought the world was shaped like a pear and was much smaller. Yes Really). Columbus would go on to "discover" the Americas (hard to "discover" a place that natives lived in for 11,000 years and the Viking Lief Erickson set foot on in 1001 A.D.). This new revelation would set off a golden age for Spain bringing unimaginable wealth.