occurred in the River Plate during this time, and the only chronicler was a German soldier named Ulderico Schmidt (or Ulrico Schmidl). Schmidt came over to the River Plate with Don Pedro and stayed there for eighteen years, fighting in almost every battle. His account of this early history of the River Plate region is the most important document from that time period. Battling the natives along the Rio de la Plata At the River Plata, the Spaniards encountered a group of roughly three thousand natives dispersed throughout the surrounding area known as the Querandíes, who shared with them their food, however scarce. In spite of this, the Spaniards soon took the natives and their generosity for granted and as a result, the Querandíes ended relations with the white men and relocated further away from the Spanish settlement. Angered by the sudden hostility, Mendoza sent his brother to lead a force against the natives. Even though hundreds of natives were killed, Mendoza's brother was slain as well, along with thirty of his men and several horses at the Battle of the Luján River. The natives were driven off after that bloody battle and their provisions were taken, but the fight was very costly to the Spaniards. Difficulties The colonists' city was surrounded by a hastily made thick adobe wall made of mud. Every time it rained the wall partially dissolved. Along with this occasionally deteriorating wall, the colonists had to deal with another problem: famine. Food eventually became scarce, and the residents had to resort to eating rats, mice, snakes, lizards, rawhide boots, and even the bodies of those who died. In addition to these difficulties, a coalition of the natives formed. They attacked the city again and again, many times leaving the city almost completely burned to the ground. Still suffering from syphilis, Mendoza appointed Juan de Ayolas to succeed him as captain-general. Ayolas dealt with the problem by sailing up the Parana River with a large part of the remaining force. They defeated the Guaraní, made a treaty of friendship with them, and then Ayolas found the city of Asunción (in current-day Paraguay) in 1537. Mendoza heads home While all of this was going on, Mendoza, disappointed and broken in health, embarked for Spain in 1537. He died during the voyage. He promised to send aid to his forces that he left behind in Buenos Aires. Although he