This article introduces the role of medievalisms in British and Anglophone children's fantasy literature since the 1950s, focusing on how these texts impact the development of national identity. Children's fantasy literature often contributes to a nationalistic tradition of nostalgia for the Middle Ages, glorifying and reproducing that period for contemporary readers by including medieval narratives and what Clare A. Simmons calls ‘perceived codes of values’, as well as the customary medievalised trappings: castles, knights, magicians, etc. However, in the face of globalisation, recent fantasy has begun to reflect changes in the British experience of itself and the outside world. The explosive popularity of J.K. Rowling's Harry Potter novels and the subsequent rise of other new fantasy for children have placed these new forms of medievalism on a global stage through wide translation, spin-off media and merchandise. This article is especially concerned with how these texts balance questions of racial and spatial relationships to establish insider identity for their young readers.