He was the son of Solomon ibn Labi de la Caballeria of Zaragoza and assumed the name of "Micer Pedro" upon converting to Christianity.
From his early youth he devoted himself to the study of Hebrew, Arabic and Latin languages, and gradually acquired a profound knowledge of civil and Canon law.
He won the favor of Queen Maria, who appointed him commissioner of the Cortes which convened at Monzón and Alcañiz (1436–37); and all the liberties and privileges which the Caballeria family had enjoyed for a long time were confirmed to him and his descendants.
This work, upon which he was engaged for fourteen years, was published at Bologna in 1592 by Martin Alfonso Vivaldo, who added numerous annotations showing his hostility to the Jewish race.
Soon after the completion of this work, in which he falsely accused the Jews of every imaginable vice, branding them as a cursed seed and a hypocritical, pestilential, and abandoned race, Pedro was murdered (1464), the deed having been committed, it is believed, at the instigation of Marranos.