Spanish queens have played significant roles in the history of Spain, often influencing politics, culture, and society. Notable figures include Isabella I of Castile, who united Spain through her marriage to Ferdinand II of Aragon and sponsored Christopher Columbus's voyages, leading to the discovery of the Americas. Another important queen is Queen Sofia, the wife of King Juan Carlos I, who reigned during Spain's transition to democracy. Spanish queens have often been involved in charitable work and cultural initiatives, contributing to the nation's identity and heritage throughout the centuries.