Isabella I, queen of Castile and León (born 1451)

Isabella I, also called Isabella the Catholic, was Queen of Castile and León from 1474 until her death in 1504. She was also Queen of Aragon from 1479 until her death as the wife of King Ferdinand II. Reigning together over a dynastically unified Spain, Isabella and Ferdinand are known as the Catholic Monarchs. Her reign marked the end of Reconquista and also the start of Spanish Empire and dominance of Spain over European Politics for the next century.

The Crown of Castile was a medieval polity in the Iberian Peninsula that formed in 1230 as a result of the third and definitive union of the crowns and, some decades later, the parliaments of the kingdoms of Castile and León upon the accession of the then Castilian king, Ferdinand III, to the vacant Leonese throne. It continued to exist as a separate entity after the personal union in 1469 of the crowns of Castile and Aragon with the marriage of the Catholic Monarchs up to the promulgation of the Nueva Planta decrees by Philip V in 1716.

The Kingdom of León was an independent kingdom situated in the northwest region of the Iberian Peninsula. It was founded in 910 when the Christian princes of Asturias along the northern coast of the peninsula shifted their capital from Oviedo to the city of León. The kings of León fought civil wars, wars against neighbouring kingdoms, and campaigns to repel invasions by both the Moors and the Vikings, all in order to protect their kingdom's changing fortunes.