One of the most distinguished leaders of Aragon in the early 15th century was King Alfonso. Alfonso the Magnanimous ( 1396– 1458) was the King of Aragon (as Alfonso V), Valencia (as Alfonso III), Majorca, Sardinia and Corsica (as Alfonso II), and Sicily and Count of Barcelona (as Alfonso IV) from 1416 and King of Naples (as Alfonso I) from 1442 until his death. He was one of the most prominent figures of the early Renaissance and a knight of the Order of the Dragon. Born at Medina del Campo, he was the son of Ferdinand I of Aragon (known as Ferdinand of Antequera) and Eleanor of Alburquerque. He represented the old line of the counts of Barcelona only through women, and was on his father's side descended from the House of Trastamara, the reigning House of Castile. By hereditary right he was king of Sicily and disputed the island of Sardinia with Genoa. Alfonso was also in possession of much of Corsica by the 1420s. Alfonso represents the gradual merging of the reigning house of Castile with the reigning house of Aragon. He is the grandfather of King Ferdinand II of Aragon. Alfonso was succeeded by John II of Aragon. John II the Faithless, also known as the Great (1398 – 1479 was the King of Aragon from 1458 until 1479, and jure uxoris King of Navarre from 1425 until his death. He was the son of Ferdinand I and his wife Eleanor of Alburquerque. John is regarded as one of the most memorable and most unscrupulous kings of the 15th century. John was born at Medina del Campo. In his youth he was one of the infantes (princes) of Aragon who took part in the dissensions of Castile during the minority and reign of John II of Castile. Till middle life he was also lieutenant-general in Aragon for his brother and predecessor Alfonso V, whose reign was mainly spent in Italy. In his old age he was engaged in incessant conflicts with his Aragonese and Catalan subjects, with Louis XI of France, and in preparing the way for the marriage of his son Ferdinand with Isabella I of Castile which brought about the union of the crowns of Aragon and Castile, that was to create the Kingdom of Spain.
Chapter 5, "Birth of the Spanish World"
The Story of Spain: The Dramatic History of Europe's Most Fascinating Country,
Golden Era Books,