Focussing on Yorkshire, by far the largest English county, this book examines three of the most important themes in the period described by Sir Frank Stenton as 'the first century of English feudalism': the Norman conquest, the anarchy of Stephen's reign and the nature of lordship and land tenure. In each case the book offers a strong challenge to dominant interpretations, and seeks to alter in significant ways our conception of Anglo-Norman politics and government. The first section of the book reveals that the Norman conquest of Yorkshire was a much more rapid and carefully controlled process than has hitherto been supposed; that, initially at least, it owed a great deal to the construction of castles and organisation of castleries; that during the reign of the Conqueror's youngest son, Henry I, its character changed as the king sought to bring Yorkshire under tighter central administrative control and promote monasticism there; and that its impact upon tenurial structure and terms of land tenure, although considerable, has been overestimated.