Henry IV of Castile

Henry IV of Castile (Castilian: Enrique IV; 5 January 1425 – 11 December 1474), nicknamed the Impotent, was King of Castile and León and the last of the weak late-medieval kings of Castile and León. During Henry's reign, the nobles became more powerful and the nation became less centralised.

Henry was born in 1425 at the Casa de las Aldabas (since destroyed) in Teresa Gil street of Valladolid. He was the son of John II of Castile and Maria of Aragon, daughter of King Ferdinand I of Aragon. He displaced his older sister, Eleanor, and became heir apparent to the Castilian throne as the Prince of Asturias.

At the time of his birth, Castile was under control of Álvaro de Luna, who intended to select Henry's companions and direct his education. The companions of his own age included Juan Pacheco, who became his closest confidant. The struggles, reconciliations and intrigues for power among the aristocracy, Álvaro de Luna, and the Infantes of Aragon would be constant.

On 10 October 1444, he became the first and only prince of Jaén. In 1445 he won the First Battle of Olmedo, defeating the Infantes of Aragon. After the victory at Olmedo, Álvaro de Luna's power waned, and Prince Henry and Juan Pacheco's influence grew.

Henry IV's father died on 20 July 1454 and he was proclaimed king the following day.

One of King Henry's first priorities was the alliance with Portugal. He achieved this by marrying a second time to Joan of Portugal, daughter of King Edward of Portugal, in 1455; and by meeting her brother King Afonso V of Portugal in Elvas in 1456. His other main concerns were the possibility of intervention from King John II of Navarre, establishing peace with France and Aragon, and pardoning various aristocrats. Henry IV convened the Cuéllar Courts to launch an offensive against the Emirate of Granada. The campaigns of 1455 and 1458 developed into a war of attrition based on punitive raids and avoiding pitched battles. It was not popular with the aristocracy or the people. Juan Pacheco, the Marquis of Villena, and his brother Pedro Girón were put in charge of government decisions. King Henry also took other advisors, such as Beltrán de la Cueva, Miguel Lucas de Iranzo, and Gómez de Cáceres to balance against their influence.

In 1458, King Alfonso V of Aragon died and was succeeded by his brother, John II of Navarre. King John II resumed his interference in Castillian politics, supporting the aristocratic opposition to Juan Pacheco's ambitions. With the support of the King Henry, Pacheco moved to seize Álvaro de Luna's assets, but his widow allied herself with the Mendoza family, causing a division among the aristocracy. This process resulted in the formation of a League of Nobles in March 1460. They raised a large number of noblemen, took control of expenditure, and gained the acceptance of Alfonso of Castile, the King Henry's half-brother and Prince of Asturias.

To counteract King John II's politicking, Henry IV reacted by invading Navarre in support of Charles, Prince of Viana. Charles was the heir to Navarre, and he revolted against his father John II in 1450 when he refused to cede the throne of Navarre. The campaign was a military success, but King Henry made peace with the League of Nobles in August 1461 to ward off the power of the Mendozas, which had allowed John II to intervene in Castile.