This latest addition to the English Episcopal Acta series brings together for the first time edited versions of more than 170 charters in the names of the four bishops who held the see of Ely (comprising historic Cambridgeshire) from its foundation in 1109 to 1197. These four bishops - Hervey, Nigel, Geoffrey Ridel and William de Longchamp - were amongst the most distinguished in twelfth-century England and their charters bear on many aspects of the social, economic, legal, ecclesiastical and monastic history of this period. The charters especially illustrate the position of the bishops as feudal lords, and their complex and often controversial relations with the monks of their cathedral. Of the four bishops in office before 1197, two held important secular office alongside their episcopal appointments, most notably William de Longchamp, justiciar and effective regent of England while King Richard I was absent during the Third Crusade. Acta issued in connexion with these secular offices are included in the volume, and make an important contribution to the understanding of the delegation of royal power and secular government far beyond the diocese of Ely. An extensive introduction contextualises the acta in the development of the cathedral church and the diocese of Ely.