Alfred Chester Beatty and his wife Edith were amongst the last figures of a generation of London-based collectors who created major collections of medieval manuscripts between c. 1915 and c. 1930. In shaping his collection, Beatty benefitted from the advice and example offered by older collectors, in particular Sydney Cockerell and Henry Yates Thompson, and from the skills of those who worked in museums, notably Eric Millar. This period saw major developments in the study of medieval manuscripts. Much of this work was rooted in connoisseurship and concentrated on grouping books by region, artist and date. Trained by Cockerell and others, Beatty worked to develop connoisseurial skills in order to build a collection that could rival those in museums. The publication of catalogues of a selection of his books, and the sale of part of his collection in 1932-1933, helped to draw attention to the manuscripts that he considered to be of the finest quality. At the same time, the rejection of volumes from the collection, which were often never publicly linked to his name, helped to establish the collection’s reputation for excellence and to consolidate contemporary ideas about a canon of illuminated manuscripts that were to have an important influence on both twentieth-century collecting and scholarship.