The party that stopped behind as a reserve was commanded by Domingo Irala, the real founder of the Spanish settlements in the Parana valley. The main expedition never returned. Years afterward friendly Indians brought back the tale that it had reached the slopes of the Bolivian mountains, obtained much gold and silver and started back triumphantly, but had perished to the last man in an Indian ambush not far from the Paraguay and safety. Irala waited the appointed time and then floated down the river. He and his companions were well-nigh in despair. So far as they knew, they were the only survivors of the three thousand people who had accompanied Mendoza. To the north the country was inhospitable and impenetrable, and from their experiences of the year before they knew that at the mouth of the river no provisions or succour were to be had. On their way up the river they had passed, about the twenty-fifth degree, a beautiful and fertile rolling country, covered with magnificent forests, with park-like openings, and inhabited by a large and friendly Indian population. Opposite the mouth of the Pilcomayo, where there was a large Indian village, they stopped on their downward journey, determined to settle down and take some repose from their interminable and fruitless wanderings in search of the will-o'-the-wisp Eldorado. There, in 1536, they founded the city of Asuncion, the first Spanish settlement on the Atlantic slope of South America. _The Foundation of Buenos Aires._--The failure of Mendoza, first adelantado, to establish a colony on the Plate, did not discourage others from soliciting the grant of his territory. In 1540, Cabeza de Vaca, a "conquistador" celebrated for his feats in Florida, was appointed adelantado and set out gallantly to find the second Peru, which everyone believed to exist at the headwaters of the Paraguay. Intent on reaching the interior as soon as possible, he made no attempt to establish a town and port at the mouth of the river Plate, but landed at Santa Catharina on what is now the Brazilian coast in the latitude of Paraguay, and set off across country with four hundred men and twenty horses. The distance was a thousand miles; the route led up a heavily wooded mountain range on the coast, and thence across a broken, but open, plateau, where great rivers point out the natural routes to the Parana. The soil was fertile and the Indians along the road were able to furnish considerable food supplies. Cabeza de Vaca made the journey without appreciable loss and arrived in Asuncion eager to take command and dash across to the Andes. But the sturdy Basques had selected their able countryman--Domingo Irala--as chief of the colony and gave the new adelantado a cold welcome. Irala insisted that a reconnoitring expedition be sent before risking the body of the Spaniards. Its command was given him and he penetrated almost to the headwaters of the Paraguay. Next year Cabeza de Vaca followed, but as soon as he left the