The term "Spanish Kingdoms" refers to the various independent kingdoms that existed on the Iberian Peninsula before the unification of Spain in the late 15th century. Key kingdoms included Castile, Aragon, Navarre, and Leon. Each kingdom had its own government, culture, and language, contributing to the rich diversity of the region. The unification of these kingdoms began with the marriage of Ferdinand II of Aragon and Isabella I of Castile in 1469. Their reign marked the completion of the Reconquista in 1492, which ended Muslim rule in Granada and laid the foundation for the modern Spanish state.