The Oxford Dictionary of the Middle Ages is a major new reference resource for all key aspects of European history, society, religion, and culture from 500 to 1500. Since neighbouring areas of Asia and North Africa impinged on and helped shape the civilization of the West, relevant aspects of the Byzantine Empire, the Islamic dynasties, and Asiatic peoples such as the Avars and the Mongols are included. It is designed both for medievalists, who need a detailed and reliable reference tool for their own research and teaching, and for non-specialists, who need an accessible guide to the study of the Middle Ages. All entries are written with both audiences in mind. Over 800 scholars, guided by an international advisory board of five and an international editorial board of 26, have written the over 5,000 entries, and these entries have been lavishly supplemented by more than 500 illustrations and 50 maps. Each entry contains a brief bibliography.

Distinguishing this research resource are its balanced coverage of both the whole geographical extent of the European Middle Ages and sixteen major topics centrally important to the study of the period. Ten members of the editorial board have ensured ample coverage of geographical regions: France, Germany and Austria, Spain and Portugal, Italy, Sicily, and Latin Greece, the Low Countries, England, Scotland, Ireland, and Wales, Scandinavia and Iceland, and Central and Eastern Europe. In addition sixteen members of the board have ensured similar coverage of major international topics: art and architecture, archaeology, science, medicine, technology, law, ecclesiastical history, intellectual history, philosophy, social and economic history, Romance, Germanic, and Slavic languages and literatures, Islam, Judaica, medieval Latin, and music and liturgy. There are also separate and substantial entries on women and children in each of the geographical areas represented and in Jewish and Islamic society.