John of Castile, Lord of Valencia de Campos

Infante John
Lord of Valencia de Campos Consort Lord of Biscay
Coat of Arms of Infante John of Castile.
Born	15 May/25 July 1260 Seville
Died	25 June 1319 (aged 58–59) Pinos Puente
Burial	Burgos Cathedral
Spouse	Margaret of Montferrat María II Díaz de Haro
Issue	Alfonso, Lord of Valencia de Campos Lope Díaz de Haro Juan el Tuerto María Díaz II de Haro
House	House of Burgundy
Father	Alfonso X of Castile
Mother	Violant of Aragon
Religion	Roman Catholicism

John of Castile, called the "el de Tarifa" (Spanish: Juan de Castilla "el de Tarifa"; 1262–25 June 1319) was an infante of Castile and León. He was engaged in a decades long fight for control over the Lordship of Biscay with Diego López V de Haro, the uncle of his wife.

He was born before 15 April 1262 in Seville, the son of Alfonso X, King of Castile and León and Queen Violant of Aragon. In 1296 during the minority of his nephew Ferdinand IV of Castile, John was declared King of León, of Seville and Galicia, although in 1300 he reconciled with Ferdinand IV and entered his service. In 1312 after the death of Ferdinand IV, he was appointed guardian of his son Alfonso XI, whom he served alongside Queen María de Molina and Infante Peter of Castile, Lord of Cameros.

He was the Lord of Valencia de Campos and Biscay, by his marriage to María Díaz de Haro, and was also Lord of Baena, Luque, Zuheros, Lozoya, Villalón,Oropesa, Santiago de la Puebla, Melgar de Arriba, Paredes de Nava, Medina de Río Seco and Castronuño, and he served as alférez (armour-bearer) of the King and mayordomo mayor (high steward) of the King. He was also Adelantado of Andalusia. He died in 1319 at Pinos Puente, in the battle of Sierra Elvira, also known as the disaster of Vega de Granada.