NOTE.—This Yucatan bas-relief follows a photograph by Rosny (1880), reproduced in the _Mém. de la Soc. d’Ethnographie_, no. 3 (Paris, 1882).] CHAPTER IV. THE INCA CIVILIZATION IN PERU. BY CLEMENTS R. MARKHAM, C. B. THE civilization of the Incas of Peru is the most important, because it is the highest, phase in the development of progress among the American races. It represents the combined efforts, during long periods, of several peoples who eventually became welded into one nation. The especial interest attaching to the study of this civilization consists in the fact that it was self-developed, and that, so far as can be ascertained, it received no aid and no impulse from foreign contact. It is necessary, however, to bear in mind that the empire of the Incas, in its final development, was formed of several nations which had, during long periods, worked out their destinies apart from each other; and that one, at least, appears to have been entirely distinct from the Incas in race and language.[1138] These facts must be carefully borne in mind in pursuing inquiries relating to the history of Inca civilization. It is also essential that the nature and value of the evidence on which conclusions must be based should be understood and carefully weighed. This evidence is of several kinds. Besides the testimony of Spanish writers who witnessed the conquest of Peru, or who lived a generation afterwards, there is the evidence derived from a study of the characteristics of descendants of the Inca people, of their languages and literature, and of their architectural and other remains. These various kinds of evidence must be compared, their respective values must be considered, and thus alone, in our time, can the nearest approximation to the truth be reached. [Illustration: MAP IN BRASSEUR’S POPUL VUH.] The testimony of writers in the sixteenth century, who had the advantage of being able to see the workings of Inca institutions, to examine the outcome of their civilization in all its branches, and to converse with the Incas themselves respecting the history and the traditions of their people, is the most important evidence. Much of this testimony has been preserved, but unfortunately a great deal is lost. The sack of Cadiz by the Earl of Essex, in 1595, was the occasion of the loss of Blas Valera’s priceless work.[1139] Other valuable writings have been left in manuscript, and have been mislaid through neglect and carelessness. Authors are mentioned, or even quoted, whose books have disappeared. The contemplation of the fallen Inca empire excited the curiosity and interest of a great number of intelligent men among the Spanish conquerors. Many wrote narratives of what they saw and heard. A few studied the language and traditions of the people with close attention. And these authors were not confined to the clerical and legal professions; they included several of the soldier-conquerors themselves.[1140]