The lengthy period of the Avignon papacy in the fourteenth century created circumstances in which the burgeoning bureaucracy of the papal curia could flourish. Papal involvement in the everyday business of the church at local level reached its fullest extent in the years before the Great Schism. This book examines the impact of that involvement in Scotland and northern England, and analyses the practical effect of theories of papal sovereignty at a time when there was still widespread acceptance of the role of the Holy See. The nature and importance of political opposition, from both crown and parliament, is investigated from the standpoint of the validity of the complaints as indicated by local evidence, and a new interpretation is offered of the various statutory measures taken in England in Edward III’s reign to control alleged abuses of papal power. Points of similarity and difference between Scotland and England are also given due emphasis. This is the first work to attempt to analyse the full breadth of papal involvement in late medieval Britain by utilising the rich local sources in association with material from the Vatican archives.