ABSTRACT
This chapter tries to show that documentary evidence from the tenth century confirms the general currency given to Christian Platonist beliefs, advancing in particular the significance and expression of number, and that this also extended to geometric expressionism. In examining the monastic architecture of the period, there seems little doubt that Glaber's 'white mantle of churches' referred to a second wave of building and rebuilding in the monastic revival after the middle of the tenth century, which resulted in abbeys becoming larger and architecturally more complex. The building of the second abbey church at Cluny took place between 948 and 981 during the abbacies of Mayeul and Odilo. The symbolic content of the architecture and its continuity into the Ottonian period are borne out by the Registrum Gregorii of about 983 from Trier in which the architecture of Gregory's picture appears to symbolize both a church and the Church and in which Otto is shown enthroned within a baldaquin.
