In July of the year 1263, the Dominican friar Pablo Christiani met to debate Rabbi Moses ben Nahman, sometimes known as Nahmanides, to discuss whether Jesus was the messiah, and thus whether Christianity or Judaism had a greater claim to truth. They conducted this debate in the court of King James of Aragon, who famously guaranteed the rabbi’s freedom of speech, allowing Nahmanides to advance even arguments that, being regarded as heretical by Christian clergy, would have otherwise caused him to be imprisoned or worse. These proceedings are known, famously, in history as the Disputation of Barcelona. To understand fully the context of this debate, one has to know something more about the Dominican friar Pablo Christiani: he was not born Pablo Christiani. In fact, he was born as a Sephardi Jew with the birth name of Saul. Only later in life, having lived as a Jewish man and having been exposed to some Jewish learning, did he convert to Catholicism. Joining the Dominican order as a friar, Saul—newly dubbed Pablo—dedicated his life to converting the Jews, possibly with argument and persuasion—he liked to use statements from talmudic texts as evidence for Christian theology—but also through the threat of violence and force. What is it that would so compel a person to turn against his own family, his own teachers, his own neighbors, his own religion—and not as a matter of indifference but as a matter of revenge on the sources of his own formation? That is one of the questions that runs underneath a new story by the legendary essayist, novelist, and short-story writer Cynthia Ozick. This work is called “The Conversion of the Jews,” and it was published in Harper's in May 2023. Ozick’s “The Conversion of the Jews” follows a twenty-four-year-old scholar of words and languages named Solomon Adelberg, as he, in the early 1930s, attempts to discover how and why Christiani undertook his conversion. These questions lead Adelberg to a hollowed-out monastery in the Judean desert, through the occult world of mysticism and magic, and eventually to attempting a séance with the icon of a saint in his Lower East Side apartment. To discuss that story, and the many ideas, themes, and questions it raises, Cynthia Ozick joins Mosaic’s editor Jonathan Silver on our podcast (originally broadcast in 2023).