The manuscript was made for Catherine of Cleves, duchess of Guelders and countess of Zutphen, who clearly asked for, and received, one of the richest Books of Hours ever created. Not only are there 157 miniatures (9 others are missing), but they are also framed by borders of remarkable inventiveness. Planned with extraordinary care, the book luxuriates in pictures and texts. It contains, for example, a cycle of illustrated Weekday Hours plus a complete set of illustrated weekday Masses. Reproduced here is the miniature for the Saturday Mass of the Virgin. The miniature illustrates how Christ--the God-Man--is the uniquely qualified mediator between God and man. It also illustrates how Mary plays the vital roles of mediatrix for mankind, coredemptrix with Christ, and dispensatrix of God's grace.
The anonymous illuminator is named after this masterpiece, the greatest of all Dutch Books of Hours. His rich palette, extraordinary powers of observation, and facility with complex iconography rank the Cleves Master as one of the greatest of all illuminators.