Students of the architecture of castles are aware that this subject presents much more difficult questions than does the architecture of churches. Those who are seriously working on castle architecture are very few in number, and are as yet little known to the world at large. From time to time, books on castles are issued from the press, which show that the writers have not even an idea of the preliminary studies without which their work has no value at all. It is hoped that the sketch of castle architecture from the 10th century to the 13th, which is given in the last chapter, may prove a useful contribution to the subject, at any rate in its lists of dated castles. The Pipe Rolls have been too little used hitherto for the general history of castle architecture, and no list has ever been published before of the keeps built by Henry II. But without the evidence of the Pipe Rolls we are in the land of guesswork, unsupported, as a rule, by the decorative details which render it easy to read the structural history of most churches. My warmest thanks are due to Mr Duncan H. Montgomerie, F.S.A., for his generous labour on the plans and illustrations of this book, and for effective assistance in the course of the work, especially in many toilsome pilgrimages for the purpose of comparing the Ordnance Survey with the actual remains. I also owe grateful thanks to Mr Goddard H. Orpen, R.I.A., for most kindly revising the chapter on Irish mottes; to Mr W. St John Hope (late Assistant Secretary of the Society of Antiquaries), for information on many difficult points; to Mr Harold Sands, F.S.A., whose readiness to lay his great stores of knowledge at my disposal has been always unfailing; to Mr George Neilson, F.S.A.Scot., for most valuable help towards my chapter on Scottish mottes; to Mr Charles Dawson, F.S.A., for granting the use of his admirable photographs from the Bayeux Tapestry; to Mr Cooper, author of the _History of York Castle_, for important facts and documents relating to his subject; to the Rev. Herbert White, M.A., and to Mr Basil Stallybrass, for reports of visits to castles; and to correspondents too numerous to mention who have kindly, and often very fully, answered my inquiries. ELLA S. ARMITAGE. WESTHOLM, RAWDON, LEEDS. CONTENTS PAGE PREFACE vii CHAPTER I INTRODUCTORY 1 CHAPTER II ANGLO-SAXON FORTIFICATIONS 11 CHAPTER III ANGLO-SAXON FORTIFICATIONS--CONTINUED 31 CHAPTER IV DANISH FORTIFICATIONS 48 CHAPTER V THE ORIGIN OF PRIVATE CASTLES 63 CHAPTER VI DISTRIBUTION AND CHARACTERISTICS OF MOTTE-CASTLES 80 CHAPTER VII