The question of what constitutes a just ruler is one that has been addressed for millennia. In Medieval Europe ideal kingship was based on a notion of Charlemagne, who considered himself a new David, or on Arthur, who probably never existed. Most serious biographies of rulers were written in Latin, by clerics. Delogu (romance languages and literatures, University of Chicago) focuses on the point when French royal biography appeared in the vernacular. The first of these was Joinville's Vie de Saint Louis a personal chronicle of the crusades Of Louis IX, which Joinville experienced. She ends with Christine de Pizan's life of Charles V. Delogu notes that a comparative study of vernacular biography has not been done before, the form being considered derivative and formulaic. In her study she argues that each of the biographies, two in prose, two in verse and one in the French form known as a lai, reveal decidedly different, often ambiguous views on the good prince. She sees a great difference from Joinville's image of the saintly crusader and Pizan's approving portrait of the competent administrator. While historians have mined these works for many years, their literary properties have been largely ignored. Degolu rectifies this lapse. Annotation ©2009 Book News, Inc., Portland, OR (booknews.com)