The Lancelot-Grail romance in French (also known as the Vulgate Cycle of Arthurian Romance) was one of the most popular vernacular texts of the Middle Ages, surviving in whole or in part in close to 200 manuscript copies. Several clusters of manuscripts were produced by the same or closely similar scribes, decorators and artists. These clusters are particularly important in allowing comparisons that shed light on production practices and the choices that were made in terms of the selection and treatment of subjects for illustration and the placing of illustrations in the text. We chose three manuscript copies made in Flanders (probably Saint-Omer, Ghent or Tournai) in the second decade of the fourteenth century to conduct a comparative study with a view to determining what strategies were at play in the construction of the illustrative programmes and their relationships. Our selected manuscripts include BL Additional 10292-4 which has more illustrations than any other surviving copy and was the basis for H.O. Sommer's edition, published in 8 vols., 1909-1913.