Having founded his settlement, Mendoza set himself to deal with the Indians and to bring them into subjection. In a very short while he found out that it was a very different tribe of aborigines with which he had to deal to the peace-loving inhabitants of Peru and the north-west. The agile, hardy, and fierce Pampa Indians, having once fallen foul of the invaders, allowed them no respite. Attacked by day and night, deprived of all supplies of food, Mendoza's troops began to suffer from exhaustion and hunger, to say nothing of the wounds inflicted by their enemies. In the end, the leaders had to admit to themselves that the place was no longer tenable. Nevertheless, neither Mendoza nor his men had any intention of abandoning permanently these fertile plains through which ran the great rivers. The scarcity of minerals in these districts had now become sufficiently obvious to them; yet even to men in quest of little beyond gold the extraordinary fertility of the alluvial soil was not altogether lost. With a courage and pertinacity which does the adventurers every credit, they determined, instead of abandoning the river and putting out to sea, to sail far up-stream into the unknown, and to seek their fortune inland. Mendoza's expedition first of all established itself for a while on the site of Sancti Spiritus, Cabot's old abandoned fort, which they now rechristened Corpus Christi. Shortly after their arrival at the place, Mendoza himself, who had doubtless suffered many disillusions concerning the gold and precious stones of these districts, and whose health had given way beneath the stress of the hardships and of the numerous precarious situations in which he had found himself, set sail for Spain. It was to be his fate never to return to his native land, since he died on his way home. Juan de Ayolas was now left in command of the Spanish force. He was an able commander, and a man of determined character, eminently fitted to conduct an expedition such as this. Without hesitation, the new leader purposed to make his way farther up the stream. He got together the ships once again, and, manning them, he made his way from point to point along the great river system, attacked here and there by the Indians on the banks, and occasionally challenged by flotillas of canoes, which boldly came out to assume the aggressive. But in every case the lesson taught the Indians was a severe one, and, undeterred by the hostility shown him, Ayolas sailed inland until he came to Asuncion in Paraguay. At this spot the expedition came to a halt, and the weary pioneers landed, and immediately became lost in admiration of the fertile and delightful country in which they now found themselves.