The last two volumes, which are in general finer, were worked on by the anonymous illuminators known as the Master of Anthony of Burgundy (identified by some writers with Philippe de Mazerolles), the Master of Margaret of York, and the Master of the Dresden Prayer Book, the last as an assistant to the Master of Anthony of Burgundy. These masters are named after prominent works or patrons of theirs. It appears that the project was split in half from an early stage, as the scribes who wrote the text and the style of border decoration (also the work of specialists) differ between volumes 1-2 and 3-4.