Charles V. had too many anxious concerns in Europe to take an active part in organising expeditions to the New World, and he found it convenient to commit the task to wealthy nobles. Pedro de Mendoza had enriched himself at the sack of Rome and had dreams of still greater wealth. Accordingly he obtained a grant of the whole country from the River Plate to the Straits of Magellan, with a salary of 2,000 ducats a year as Governor, a similar sum as an official allowance, and valuable privileges as to ransom and booty. In return, he engaged to take out an adequate force and to open up a land route from the Atlantic to the Pacific. In August, 1534, he set sail from Cadiz with eleven ships and 800 men. This was the largest expedition which had ever sailed from Europe to the New World. Mendoza seems to have been an enterprising leader, but his lack of experience brought many unnecessary hardships upon his followers. The fleet entered the River Plate in January, 1535, and Mendoza landed on the right bank and founded the city of Buenos Aires, "so named in regard of the freshness of the air, and the healthfulness of his men, during their abode there."[21] The Adelantado, or Governor, was eager to push up the great rivers and discover a land fabulously rich in gold, such as was then enriching many of his more fortunate countrymen. But still the difficulties were insuperable; the Indians were implacably hostile and cut off all foraging parties; the Spaniards had come with inadequate provisions and were frequently in danger of starvation. Many died of their privations, and the site of Buenos Aires was abandoned within a year of its foundation. Mendoza's lieutenants made many adventurous expeditions up the vast waterways and the ill-fated Azolas founded Asuncion in 1536.[22] But their deeds belong more to the history of Spanish conquest than to Argentina proper. The estuary of the Plate was subject to sudden storms, and Mendoza, having lost eight ships and being thoroughly wearied by his misfortunes, decided to return home. On the voyage he fell ill and died, and of his large force not more than one hundred and fifty survived their privations and dangers. A highly interesting and important matter should here be mentioned. The Spaniards brought only thirty mares and seven stallions for breeding purposes, but a Portuguese mariner states thirty years later the country near the coast was full of horses. [Illustration: TROOP OF MARES.]