The Amautas, or learned men of the later Inca period, preserved the names of sovereigns of the Pirua dynasty, commencing with Pirua Manco, and continuing for sixty-five generations. Lopez conjectures that there was a change of dynasty after the eighteenth Pirua king, because hitherto Montesinos, who has recorded the list, had always called each successor son and heir, but after the eighteenth only heir. Hence he thinks that a new dynasty of Amautas, or kings of the learned caste, succeeded the Piruas. The only deeds recorded of this long line of kings are their success in repelling invasions and their alterations of the calendar. At length there appears to have been a general disruption of the empire: Cuzco was nearly deserted, rebel leaders rose up in all directions, the various tribes became independent, and the chief who claimed to be the representative of the old dynasties was reduced to a small territory to the south of Cuzco, in the valley of the Vilcamayu, and was called “King of Tampu Tocco.” This state of disintegration is said to have continued for twenty-eight generations, at the end of which time a new empire began to be consolidated under the Incas, which inherited the civilization and traditions of the ancient dynasties, and succeeded to their power and dominion. It was long believed that the lists of kings of the earlier dynasties rested solely on the authority of Montesinos, and they consequently received little credit. But recent research has brought to light the work of another writer, who studied before Montesinos, and who incidentally refers to two of the sovereigns in his lists.[1158] This furnishes independent evidence that the catalogues of early kings had been preserved orally or by means of _quipus_, and that they were in existence when the Spaniards conquered Peru; thus giving weight to the testimony of Montesinos.