They were both native Spanish as well as part of "another family from France."

The House of Trastámara began as a cadet branch of the House of Ivrea, which came to rule over Castile and Leon when Raymond of Burgundy, a younger son of Guillaume I, count of Burgundy, married Urraca of León, the daughter and heir of Alfonso VI of León and Castile. Urraca and her father were both members of the Jiménez dynasty, who were themselves of mixed ethnicity: Basque, other Iberian, and Visigoth.