Cobo had prepared himself for his somewhat ambitious undertaking by his studies at the Jesuit college at Lima, by keeping in mind his plan for many years, and by persistent and systematic observations and inquiries during his many and extensive journeys. He was born in Lopero, a town of Jaén in Spain, in 1582. He left Spain for America in 1596. He was carried away on the current of emigration, moved by the desire for adventure and wealth that set strongly towards Peru in the last half of the sixteenth century. He visited the Antilles and Venezuela, and arrived at Lima in the beginning of 1599. Through the influence of a Jesuit whom he met on the voyage from Panama to Callao, he obtained a scholarship, and entered the college of San Martín. Fifteen years later, in 1615, having been admitted to the Society, he was sent to Juli, and for three years was engaged in missionary work at Potosí, Cochabamba and La Paz. From 1618 to 1621 he was rector of the college at Arequipa, and afterwards, for five years, resided at the house of the Jesuits in Pisco. From 1627 to 1630 he was the rector of the college at Callao; but at the end of this service he was sent to Mexico, where he remained for twenty years. At a date not known with certainty he returned to Lima, and died there on the 9th of October, 1657, at the age of seventy-five. During the sixty-one years of his residence in America he gathered the detailed information that was embodied in his _Historia_, which, with the exception of the fragments already mentioned, remained in manuscript two hundred and fifty years.[126] In the seventh chapter of the _Historia de Lima_ Cobo gives a glimpse of the valley of the Rimac as it appeared to him about a hundred years after the conquest: [Sidenote: Valley of the Rimac] “The river of Lima is the larger, the other is called Caraguayllo, and rises in the province of Canta, in the general cordillera, about twenty leagues from the sea, into which it empties two leagues from the mouth of the river of Lima. The irrigating ditches that lead out from these two rivers are innumerable; they are distributed throughout the valley; some are so big at their beginnings that they appear to be rivers of considerable volume, which draw their water from the river of Lima; we call them ditches of Surco, because they lead to a town of that name, the lands of which they irrigate, as well as those of three other towns, and altogether more than forty estates, or ranches, of Spaniards, residents of this city, and there is among them an estate comprising two leagues of land. [Sidenote: The fair prospect of the Rimac valley]