Alfonso was born in
Valladolid in 1286. Towards the end of 1291, King
Sancho IV of Castile and
Juan Núñez I de Lara, head of the
House of Lara, in the effort to forge a political alliance, decided to
betroth Alfonso to
Juana Núñez de Lara, Juan Núñez I's eldest daughter. He was 5 years old at the time. Alfonso did not survive the year however and the subsequent political alliance fell apart as Juan Núñez I went into self-imposed exile and rebellion against Sancho IV. Alfonso de Castilla y Molina died in Valladolid in 1291 at five years of age. == Death, burial and legacy ==