Spanish doctor of Jewish origin born at Burgos about 1270 and died to 1340. Converted to Christianity when he was over 50 years, he had received a good Jewish education, and knew Arabic and Hebrew philosophy, as well as the Kabbalah.
He was one of the intellectuals of greater prestige of their community, although personal disappointments and disappointment to messianic movements that culminated in failure came to him, after long years of doubts, to Christianity. A dream which he understood as revelatory meant the definitive impulse. From the moment of his baptism became enthusiastic defender of Christianity against his former coreligionists, who wanted to absolutely convince their "errors" using own Jewish sources. Like other converts from the following centuries, Abner, who had already taken the name Maestre Alfonso of Valladolid (or Burgos), defended that only with hand hard and persecution could be Jews "to come out of its obstinacy".
When he was still a Jew he wrote a Supercomentario to the exhibition of Abraham ibn Ezra on the Decalogue. It justified its conversion into Milhamot Adonay ('wars of the Lord'), and wrote in Hebrew other apologetic works, arguing, for example, with his old pupil Isaac ibn Policar (thumb); the infanta Blanca Mrs. oversaw the translation of several of these works into Spanish. Already Christian, wrote in Hebrew the Moreh sedeq, poured to the Spanish as the desk of Justice, where he argues the superiority of Christian morality, as well as other works apologetic and controversial (harmony of the laws, the book of the three graces (or beliefs), the offering of jealousy, etc.), where he argues with Jewish intellectuals. In other writings in Hebrew, before and after conversion, he defended a kind of determinism interspersed with ideas about predestination and astrology.
BAER,. history of the Jews in Christian Spain. 2 vol. (Madrid: Altalena, 1981).
SÁENZ-BADILLOS, A. Hebrew literature in medieval Spain. (Madrid: Fundación Amigos de Sefarad, 1991).
SÁENZ-BADILLOS, TARGARONA, J. Dictionary of Jewish authors (Sefarad. 10th - 15th centuries). (Córdoba: El Almendro, 1990).