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.

There is no doubt that to the new-comers the country in the neighbourhood of Asuncion, with its pleasant valleys, rolling country, and forest-covered hills, must have come in the shape of a relief after the apparently interminable passage of the plains.  It was the spot at which the pioneer would naturally halt, and endeavour to found his settlement.

The Guarani Indians extended but a cold welcome to the daring adventurers.  Their temperament was by nature far less warlike than that of the savage and intrepid natives in the regions of the coast.  These Guarani Indians, nevertheless, made some show of aggression, and would doubtless have been glad to scare away these undesired strangers.  Owing to this, a collision between the two forces occurred; but so crushing was the defeat of the Indians that they resigned themselves submissively to the Spaniards, and henceforth became a vassal tribe, lending assistance to their white masters in both civil and warlike occupations.