 This prejudice climaxed in the summer of 1391 when violent anti-Jewish riots broke out in Spanish cities like Barcelona To linguistically distinguish them from non-converted or long-established Catholic families, new converts were called conversos, or New Catholics.This event though must be understood in the context of the fierce civil war and new politics that Peter the Cruel had brought to the land, and not be confused with spontaneous anti-semitic reactions to the plague seen in northern Europe.According to Don Hasdai Crescas, persecution against Jews began in earnest in Seville in 1391, on the 1st day of the lunar month Tammuz (June).