Habsburg Spain
The marriage of Isabella I of Castile and Ferdinand II of Aragon in 1469 resulted in the union of the two main crowns, Castile and Aragon, which eventually led to the de facto unification of Spain, after the culmination of the Reconquista with the conquest of Granada in 1492 and of Navarre in 1512-1529. Isabella and Ferdinand were bestowed the title of "Catholic King and Queen" by Pope Alexander VI in 1494, and the term Monarchia Catholica (Catholic Monarchy, Modern Spanish: Monarquía Católica) remained in use for the monarchy under the Spanish Habsburgs. The Habsburg period is formative of the notion of "Spain" in the sense that was institutionalized in the 18th century.