Infante Don Fernando was a Spanish royal born in 1452, the son of King Juan II of Aragon and Queen Juana Enríquez. He was a member of the House of Trastámara and played a significant role in the politics of his time, particularly in the context of the Spanish Reconquista. He is best known for his marriage to Princess Isabel of Castile, which united two powerful kingdoms. This union eventually led to the establishment of a unified Spain under their grandson, King Charles I. Don Fernando's legacy is intertwined with the early formation of modern Spain and its imperial ambitions.