Book excerpt: Throughout the period 800-1250, English culture was marked by linguistic contestation and pluralism: the consequence of migrations and conquests and of the establishment and flourishing of the Christian religion centred on Rome. In 855 the Danes 'over-wintered' for the first time, re-initiating centuries of linguistic pluralism; by 1250 English had, overwhelmingly, become the first language of England. Norse and French, the Celtic languages of the borderlands, and Latin competed with dialects of English for cultural precedence. Moreover, the diverse relations of each of these languages to the written word complicated textual practices of government, poetics, the recording of history, and liturgy. Geographical or societal micro-languages interacted daily with the 'official' languages of the Church, the State, and the Court. English and English speakers also played key roles in the linguistic history of medieval Europe. At the start of the period of inquiry, Alcuin led the reform of Latin in the Carolingian Empire, while in the period after the Conquest, the long-established use of English as a written language encouraged the flourishing of French as a written language. This interdisciplinary volume brings the complex and dynamic multilingualism of medieval England into focus and opens up new areas for collaborative research.