The Argentine nation proper began its existence when the creole mounted his horse and took to cattle-breeding on the plains. The possession of horses, as much as of firearms, gave the gaucho his military predominance over the fiercest aborigines, and the horse was also the cornerstone of his industrial system. The cattle of the open pampa gave him an unlimited supply of the best food, and his horses enabled him to procure it with a minimum of effort. Irala's successors repeatedly tried to establish a colony near the mouth of the Plate, but they were not successful until the creoles on horseback had pushed their way south along the pampa and driven back or subdued the wandering Indians. In 1560, the Guaranies of Paraguay were definitely crushed in the horribly bloody battle of Acari, but it was not until 1573 that the Spaniards from Asuncion succeeded in founding a city south of the confluence of the Parana and Paraguay. Santa Fe was the first Spanish settlement on the Plate in territory now a part of the Argentine Republic. The man who led the creoles to the pampa was Juan de Garay, a Basque, who had been one of the soldiers in the army that conquered Peru. His energy and vigour, and the bravery of the creole cavalry who followed his expeditions down the river and over the pampas, at length opened up communication from Paraguay to Europe and gave Spain a seaport on the South Atlantic. Curiously enough, in the very year that Garay founded Santa Fe, the Spaniards from Peru founded Cordoba--the most eastward of the Andean settlements. Their hard riders had pushed on from Cordoba, reconnoitring as far as the Parana and there ran across Garay's men. The two currents of Argentine settlements met almost at the beginning, though two centuries were to elapse before they completely coalesced. Eight years later, Garay succeeded in founding Buenos Aires after Zarate, the third adelantado, had failed as badly as any of his predecessors. Garay, by sheer force of energy and fitness, became the real ruler of the settlements. Active, far-sighted, and able, he perceived that a purely military establishment at the mouth of the river was foredoomed to failure. To be permanent, the port and town must be self-sustaining, and therefore must be surrounded by farms and ranches and be accessible by land from the upper settlements. In the spring of 1580, the acting governor sent overland from Santa Fe two hundred families of Guarany Indians, accompanied by a thousand horses, two hundred cows, and fifty sheep, besides mares, carts, oxen, and other necessaries. The soldiers of the convoy were mostly creoles born in Paraguay. Boats carried down from Santa Fe arms, munitions, seed grain, tools, and whatever in those rude days was essential to a settlement. He, himself, went by land with forty soldiers, following the highland that skirts the west bank of the Parana from Santa Fe to Buenos Aires.