Much as students would now prize the information that was collected by the Spaniards who first overran the New World, they can only obtain a small fraction of it. In these days, when scientific methods are understood, and all evidence can be sifted and receive its relative weight, much of that evidence is lost. Of all the narratives and reports furnished to Herrera, for his history of the Indies, and of which he made such scanty and unintelligent use, very few have been preserved. Diligent search, for which we have to thank Don Pascual de Gayangos, has brought four such documents to light, relating to ancient Peruvian history, translations of which have been selected by the Council of the Hakluyt Society to form a volume of their series. The originals are manuscripts in the National Library at Madrid, marked B 135.

The first of these manuscripts is a report on the fables and rites of the Yncas, addressed by Christoval de Molina, the priest of the hospital for natives, at Cuzco, to Dr. Don Sebastian de Artaun, the bishop of that ancient capital. It must have been written between 1570 and 1584; the period during which Artaun was bishop of Cuzco.

The second is an account of the antiquities of Peru, by an Indian named Juan de Santa Cruz Pachacuti-yamqui Salcamayhua. His great-great grand parents were living at the time of the Spanish conquest of Peru; so that the author may have written in about 1620.