In 1391, Astruc Remoch was baptized into the Roman Catholic Church, taking the name Francisco Dias-Carni. Following his conversion, Remoch's belief in the Catholic doctrine of Extra Ecclesiam Nulla Salus was so strong that he endangered his old Jewish friend En-Shealtiel Bonfos, (probably a son of the physician Isaac Bonfos born Shealtiel of Falces), in his efforts to get Bonfos to convert as well.
Remoch (Francisco) wrote a letter to his friend in Hebrew, critical of Judaism and supportive of the beliefs of Christianity. In response, Remoch received two letters. Bonfos composed a careful response to what was a very delicate topic during the Inquisition, avoiding any statements that the Church might find offensive.
Solomon first apologizes for his interference in matters that are none of his business, then insists that as a Jew he cannot remain silent amidst the argument, and continues to argue that the Christian belief system was unsupportable, stating, "You twist and distort the Bible text to establish the Trinity."