The governor, in order to provide what was necessary for the exploration of this country as it beseemed the service of His Majesty, sent, without delay, for Gonzalo de Mendoza to recall him and his men from the land of the Arianicosies. Before leaving their village, however, he was to endeavour to get the Indians to return to their houses and pacify them.

Soon after the arrival of Francisco de Ribera and his six Spaniards at the port of Los Reyes, all the people there began to suffer from fevers, so that there were not sufficient men to mount guard in camp. Even the Guaranís were sick of this malady, and several died.

Gonzalo de Mendoza wrote that all his people were also ill of the fever, and that he was sending in the brigantiues all the sick and infirm. He had not been able to make peace with the Arianicosies, though he had several times made friendly overtures and offered them presents. Yet in spite of this they came every day and attacked him. The country, he said, abounded in provisions, both in the fields and lakes. Besides the provisions he had sent in the brigantines, a large quantity was left for the natives. The sickness that had attacked all the people was attributable to the pollution of the water, which had become brackish as it rose.