Which country was King Ferdinand and Queen Isabella from?

King Ferdinand and Queen Isabella were originally from Spain, specifically from the Kingdom of Castile and the Kingdom of Aragon, which united to form modern Spain. Their marriage in 1469 was significant as it laid the foundation for the unification of Spain, which became a powerful nation in the late 15th century. This unification was a pivotal moment that led to significant events in European history, including the sponsorship of Christopher Columbus's voyage in 1492, which resulted in the European discovery of the Americas. The influence of Ferdinand and Isabella in Spanish politics, culture, and exploration underscores their importance in shaping Spain's identity during the time. The other options, while representing prominent European nations, do not correlate with the historical background of Ferdinand and Isabella.