Two manuscripts hold a place of vital importance in all theories of the evolution of Byzantine art: the Joshua Roll or Rotulus in the Vatican Library, cod. Palat. gr. 431,1 and the Paris Psalter in the Bibliotheque Nationale, Paris, cod. gr. 139. Closely related in style, these two controversial manuscripts present much the same problem in so far as the relationship between illustrations and text is concerned.2 In each case, authorities have accepted without question a tenth century date for the text, but have disagreed on the time of production of the miniatures which have been dated as early as the fifth and as late as the tenth century. On a solution of the problem of the date of the miniatures of Rotulus and Psalter, rests, in good part, our understanding of the evolution of Byzantine art in general, and our conception of the Early and Middle Byzantine periods in particular. In this article, only the Joshua Roll will be treated, not for questions of artistic style and quality, but for one limited aspe...