St Swithun was an obscure ninth-century bishop of Winchester about whom little was, and is, known. But following the translation of his relics from a conspicuous tomb into the Old Minster, Winchester, on 15 July 971, the massive rebuilding of the cathedral, and a vigorous publicity campaign by Bishop Aethelwold (963-84), St Swithun became one of the most popular and important English saints, whose cult was widespread not only in England but also in Ireland, Scandinavia, and France. The present volume includes new and full editions of all the relevant texts – hagiographical, liturgical, and historical – in Latin, Old English, and Middle English, many of which have never been published before: these illuminate the origins and development of St Swithun’s cult. No dossier of an important English saint has been published on this scale until now: the wealth of this volume sheds new light not only on St Swithun himself, but also on the times during which his cult was at the peak of its popularity.