In this study Dr. Charles F. Fraker presents the first formal study of Jewish influences in the famous fifteenth-century <i>cancionero</i> composed at the court of the poet-king John II of Castile. In particular the four studies in this work seek to highlight the permanence of ideas amongst the works of poets known or hypothesized to be <i>conversos</i>. This book opens a bright new chapter in the study of Jewish history in Spain.