(also called John de Valladolid or John Conversus), a convert from Judaism and noted as a writer, was born about the year 1335. He is the author of two anti-Jewish works, viz. Corcordia legis, cited very often by Alfonso de Spina in his Fortalitium fidei (p. 117, 155, 169, 170 sq.), and Declaratio super Aben Esram in decem pracepta; also quoted by Alfonso de Spina. He was permitted by the king, Don Henry, to hold religious disputations with Jews, and in 1375 such a disputation took place in the cathedral of Avila, where Moses Kohen de Tordesillas was the spokesman of the Jews. The main points to be discussed were the dogmas of Christianity, the Messiahship of Jesus, his divinity and incarnation, the Trinity, and the virginity of Mary. Four discussions were held, the result of which was published by Tordesillas in his עֵזֶר הָאּמֵוּנָה, or examination of one hundred and twenty-five passages of Scripture usually urged by Christians in favor of their religion. This book, which he designated "The Stronghold of the Faith," he presented to the synagogue of Avila and Toledo. See Furst, Bibl. Judaica, 3, 435, 467; De Rossi, Dizionario storico degli Autori Ebrei (Germ. transl. by Hamberger), p. 317; the same, Bibl. Judaica antichristiana, p. 26; Gratz, Gesch. d. Juden, 8, 21 sq.; Lindo, Hist. of the Jews, p. 159; Finn, Sephardim, p. 311; Kalkar, Israel und die Kirche, p. 25. (B. P.)