In twelfth-century England there was a remarkable growth in the power of the state and the apparatus through which it governed. That growth was by no means a steady progression but was accelerated or retarded by the course of political events. The reign of Henry I, stretching over the first thirty-five years of the century, was a major period of growth. Peace created a favourable environment within the kingdom; was abroad supplied the stimulus. At that time several important developments are clearly perceived: the emergence of the first department of central government to have an existence separate from the king's travelling household; a flourishing system of royal justice; and the appearance of individuals who were making careers for themselves in administration. This book is a study of these developments. It does not pretend to be a comprehensive study of all aspects of the reign, or to be a biography of Henry I, the task currently being undertaken by Warren Hollister. Little is said about the king and the church, as this subject has been admirably covered by M. Brett's book, The English Church under Henry I. This book is primarily about the machinery and men of secular government.

That government can be regarded in some senses as a two-tier structure, with an apper level consisting of the itinerant royal household, imposed on a lower level of localized administrative agencies. Until 1106 when Henry became also ruler of Normandy, his administration in England was self-contained; this remained largely the case after 1106.