The desire to claim medieval books as objects of historic cultural significance helped to shape both collections and scholarship in the late 19th and early 20th centuries. This chapter explores how events in Flanders and England in the first quarter of the 20th century informed narratives about illuminated manuscripts as objects that could be associated with modern nation states. The approach taken here is Anglocentric, but it is ironic that an emphasis on English medieval manuscript illumination as distinctive from that produced on the Continent emerged, in part, in reaction to exhibitions in Bruges (at the heart of medieval Flanders) and Paris that were the results of international co- operation. The ideas about national cultural identity that were formulated in the first decade of the 20th century were entrenched by the destruction of the Great War, which particularly impacted Flanders and north-eastern France. In the 1920s, pre-war scholarship informed the creation of surveys of both Flemish and English manuscript art, which in turn laid foundations for later work. Ideas about manuscripts as items of national cultural heritage at the start of the 20th century have therefore shaped where and how we encounter many manuscripts today, and why many scholars have tended to treat the Channel as a barrier rather than a point of connection.