Whilst the greatest effort has been made to ensure the quality of this text, due to the historical nature of this content, in some rare cases there may be minor issues with legibility. Very few words are needed here, for the book is meant to explain its own scope. I have only to thank those to whose kindness I am deeply indebted. Professor Buckland was so good as to help me when I was striving to utilize the evidence of the Roman jurists. Chapter XLIX in particular owes much to his genial chastisement. On chapters II and LXI Mr G G Coulton has given me most valuable criticism. Yet I thank these gentlemen with some reluctance, fearing that I may seem to connect their names with errors of my own. Mr T R Glover kindly read chapter XXIX. Professor Housman called my attention to the 'Farmer's Law,' and kindly lent me Mr Ashburner's articles, to which I have referred in Appendix B. To all these, and to the Syndics of the University Press for undertaking the publication of this unconventional work, I hereby express my sincere gratitude. My reasons for adopting the method followed in this book are given on pages 5-6 and 468.