She was the first child of King John II of Castile and his first wife, Maria of Aragon.

Named after her aunt and grandmother, the Duchess of Villena and Catherine of Lancaster, she immediately became heiress presumptive to the throne of Castile upon her birth.

The Infanta was formally recognised as successor to the throne of the kingdom and sworn in as Princess of Asturias on 1 January 1423 by the Cortes of Toledo.

[1] However, the Princess of Asturias did not live long enough to succeed her father as Queen of Castile.

Princess Catherine is buried in Miraflores Charterhouse, along with her father and stepmother, Isabella of Portugal.