For many reasons the task of translating from the _Etymologies_ has been a difficult one. There is no modern critical edition of the work to afford a reasonable certainty as to the text; the Latin, while far superior to the degenerate language of Gregory of Tours, is nevertheless corrupt; the treatment is often brief to the point of obscurity; the terminology of ancient science employed by Isidore is often used without a due appreciation of its meaning. However, the greatest difficulty in translating has arisen from the fact that the work is chiefly a long succession of word derivations which usually defy any attempt to render them into English. In spite of these difficulties the study has been one of great interest. Isidore was, as Montalambert calls him, _le dernier savant du monde ancien_, as well as the first Christian encyclopaedist. His writings, therefore, while of no importance in themselves, become important as a phenomenon in the history of European thought. His resort to ancient science instead of to philosophy or to poetry is suggestive, as is also the wide variety of his ‘sciences’ and the attenuated condition in which they appear. Of especial interest is Isidore’s state of mind, which in many ways is the reverse of that of the modern thinker. It is perhaps worth while to remark that the writer has had in mind throughout the general aspects of the intellectual development of Isidore’s time: he has not attempted to comment on the technical details—whether accurately given by Isidore or not—of the many ‘sciences’ that appear in the _Etymologies_. The student of the history of music, for example, or of medicine as a technical subject, will of course go to the sources. The writer is under the greatest obligation to Professors James Harvey Robinson and James Thomson Shotwell for assistance and advice, as well as for the illuminating interpretation of the medieval period given in their lectures. He is also indebted to Mr. Henry O. Taylor and Professors William A. Dunning and Munroe Smith for reading portions of the manuscript. E. B. COLUMBIA UNIVERSITY, NEW YORK, FEBRUARY, 1912. CONTENTS PART I INTRODUCTION CHAPTER I ISIDORE’S LIFE AND WRITINGS PAGE 1. Importance of Isidore 15 a. Place in history of thought 15 b. Influence 17 2. Historical setting 18 a. The Roman culture in Spain 18 b. Assimilation of the barbarians 18 c. Predominance of the church 19