But to two other persons, not unconnected with these statesmen and men of letters, it is no less my duty and my pleasure to make known my obligations. The first of them is Mr. O. Rich, formerly a Consul of the United States in Spain; the same bibliographer to whom Mr. Irving and Mr. Prescott have avowed similar obligations, and to whose personal regard I owe hardly less than I do to his extraordinary knowledge of rare and curious books, and his extraordinary success in collecting them. The other is Don Pascual de Gayangos, Professor of Arabic in the University of Madrid,--certainly in his peculiar department among the most eminent scholars now living, and one to whose familiarity with whatever regards the literature of his own country, the frequent references in my notes bear a testimony not to be mistaken. With the former of these gentlemen I have been in constant communication for many years, and have received from him valuable contributions of books and manuscripts collected in Spain, England, and France for my library. With the latter, to whom I am not less largely indebted, I first became personally acquainted when I passed in Europe the period between 1835 and 1838, seeking to know scholars such as he is, and consulting, not only the principal public libraries of the Continent, but such rich private collections as those of Lord Holland in England, of M. Ternaux-Compans in France, and of the venerated and much-loved Tieck in Germany; all of which were made accessible to me by the frank kindness of their owners. The natural result of such a long-continued interest in Spanish literature, and of so many pleasant inducements to study it, has been--I speak in a spirit of extenuation and self-defence--_a book_. In the interval between my two residences in Europe I delivered lectures upon its principal topics to successive classes in Harvard College; and, on my return home from the second, I endeavoured to arrange these lectures for publication. But when I had already employed much labor and time on them, I found--or thought I found--that the tone of discussion which I had adopted for my academical audiences was not suited to the purposes of a regular history. Destroying, therefore, what I had written, I began afresh my never unwelcome task, and so have prepared the present work, as little connected with all I had previously done as it, perhaps, can be, and yet cover so much of the same ground.