While his father lived, the children of Eleanor de Guzman, the king's favorite, profited from appointments and royal grants.

The subsequent execution of Eleanor in Talavera in 1351, added more fuel to the fire of the rebellion by Guzman's sons, in particular her fourth born, Count Henry of Trastamara, who through marriage, ruled the northeastern portion of the kingdom.

“Just what had happened, it is somewhat difficult to discover, and the story is told that the king, listening to scandalous talk, was made to believe that his royal messenger and half-brother, Fadrique, had played the role of Sir Tristan as he had brought the lady back and that she had been a somewhat willing Isolde.” Women of Romance Countries, John Effinger (2021).

After M. Fadrique de Guzman died in battle, his body was most likely interred in a church nearby in Aragon.

Through illegitimate marriages he fathered the lineage of the Enríquez family, who became Admirals of Castile and later Dukes of Medina de Rioseco.

[2] By an unknown woman (possibly a Sephardic Jewish woman named Paloma), he had one illegitimate son: By Leonor de Angulo y Córdoba (b. c. 1340), a Castilian noblewoman, he had two illegitimate children: His descendant Juana Enriquez (1425 – February 13, 1468), was the second wife of John II of Aragon and the mother of Ferdinand II of Aragon.