 Abner of Burgos (Alfonso de Valladolid; c. 1260–1347) was perhaps the most important philosopher in the stream of Jewish Spanish rabbi-apostates in the 14th and 15th centuries. In the first part of his life, Abner was an Aristotelian Jewish philosopher. However, at the age of 60 (if Pablo de Santa Maria is a reliable source) after years of hesitation, he became a Neo-Platonic Christian, making him one of the very few philosophers (much less philosopher-rabbis) to change his philosophical opinion (and religion) during the Middle Ages. The majorities of his works are primarily polemical, and try to convince his former fellow Jews to become Christian, as he did. However, in his polemical writings, Abner built an original philosophical critique of both traditional Judaism and the Aristotelian (and Maimonidean) philosophical interpretation of Judaism. Another part of his philosophical aim was a very radical interpretation of Christianity aimed at convincing his Jewish audience that his Christianity was superior to traditional and philosophical Judaism. Abner was one of the first philosophical and scientific critics of Aristotle, as well as one of the more radical Neo-Platonic thinkers of Christianity during the Middle Ages. His works had a very important impact on Jewish philosophy at the latter end of the Middle Ages, and some of his opinions influenced, through Rabbi Hasdai Crescas, general Western philosophy.