I have tried in the present study to appraise the administrative achievement of Honorius III's pontificate by looking in general at the pope's correspondence and in particular at the originals and the copies relating to the English Crown, realm and Church. In the first part of the book I have set out from a detailed analysis of the letters to discover what can be learned about the structure and significance of the papal Chancery and its staff. An assessment of how many letters were issued under Honorius, what proportion of the correspondence was registered, the techniques of registration, the ordering of the business by the use of ‘house style’ and the development of set forms is essential to an understanding of the institution. Such an influential Chancery not only produced models for other chanceries but also created the richest archive source for studying the development of western Europe. That is not too big a claim.

In the second part I have sought to put the letters in their legal and historical context. There was one official law compilation made at the end of Honorius's pontificate, the Compilatio Quinta. I have attempted to show how and from what sources this collection was made and have considered the interpretation and application of the canon law, as it was then known, in England and in English conditions.