Isabella, Queen of Spain

(1451-1504)

   Queen of Castile from 1474. Her marriage to Ferdinand, heir to the crown of Aragon, in 1469 and the subsequent ascension of Ferdinand to the Aragonese throne in 1479 meant that for the first time, both of the major states of Spain were under the rule of a single royal couple. While each of them functioned as the primary ruler in his or her own kingdom, they ruled as a team, making their marriage more than just a personal union of two kingdoms but rather the foundation of a developing national community. Hence the reign of Isabella and Ferdinand laid the foundations for a powerful European state, which by the beginning of the 16th century had become the most powerful kingdom in Christian Europe. The children of their marriage became heirs to both parts of Spain. The marriage of their daughter Juana to Philip of Habsburg, son of the Emperor Maximilian I, hereditary prince of the Netherlands and heir to the numerous Habsburg territories in the German Empire, made their grandson Charles (Charles I of Spain, Charles V as emperor) the most powerful ruler in 16th-century Europe.

   While Ferdinand generally took the lead in matters of foreign policy, becoming a leading figure in the wars and diplomacy of the early 16th century, Isabella concentrated her efforts on Castilian domestic policy. In 1492 she and Ferdinand completed the conquest of the last Islamic principality left in Spain, the kingdom of Granada. They founded the Spanish Inquisition, and it became the first public institution that exercised power over both halves of Spain. Their policies also included the expulsion of the remaining unconverted Jews from Spain in 1492 and forcible (though for a long time mainly nominal) efforts to convert the Muslim population to Christianity; the sponsorship of Christopher Columbus' discovery of the route to the Americas in 1492; and the organization of the first set of institutions for the new American colonies. Isabella and Ferdinand also asserted royal supremacy over the higher nobility, acted to suppress brigandage and civil disorder in Castile, organized a powerful national army, and assured the crown of adequate tax revenues to meet the costs of domestic and foreign policy.

   Isabella was deeply religious, and while her religious zeal led to policies like the persecution of Jewish and Muslim minorities and the creation of the Inquisition, it also embraced efforts to reform the church, to ensure the availability of educated men for service in ecclesiastical and royal administration, and to promote devout, well-educated, and competent men to high positions in the church. In recognition of their liberation of southern Spain from Moorish rule and their many actions to favor the church, Ferdinand and Isabella received papal designation as "their Catholic Majesties" and have been known as "the Catholic Monarchs" ever since their own time.