This little book is based on a series of lectures given in the academic year 1984–85 at Cambridge, where I was living as Goodhart Professor. They were given to graduate students in law, as part of the LL.M. course in the Faculty of Law. Being based on lectures for students this book does not claim to be a work of profound research. On the other hand, the fact that the students were law graduates meant that I could raise issues in European legal history of a certain complexity not discussed in any exhaustive way in the learned literature. It also meant that I could assume an acquaintance with legal history and thus turn the course into a discussion instead of a monologue, and many issues prompted in this book were first mooted by students' questions. Since my listeners came from the continent of Europe, as well as Great Britain and the United States of America, I had sometimes to explain certain rather elementary facts of the history of the civil law to those who had grown up in the common law and vice versa. It is hoped that the reader will show understanding for this: a course on the history of European law, comprising England as well as the Continent, has, by its very nature, to take account of certain communication problems between the members of these two great families.