John of La Rochelle, or de Rupella, was a Franciscan philosopher, theologian, and preacher at the University of Paris. The first clear reference to him (in Thomas of Cantimpré) indicates that in 1238 he was already a friar and a master in theology. From John's own writings, as well as from his knowledge of and interest in philosophy, we may deduce that he had studied and perhaps taught in the faculty of arts before becoming a theologian. His Summa de Vitiis (Summa on vices and sins), which manifests his penchant for ethical questions, is directly dependent on William of Auxerre, Prevostinus, and Stephen Langton, who apparently were John's teachers in the faculty of theology. It seems that only after Alexander of Hales entered the order, in 1236, did John become acquainted with that famous theologian; thereafter John was Alexander's faithful...