There were at least five great battles that decided the liberty of South America. One of the greatest of these was that of Maipo, or Maipu, which was fought on Chilean soil. Although this battle lasted only a few hours, it was the result of years of careful preparation by San Martin. In 1814 San Martin, who was then in Buenos Aires, decided that the best way to free Argentina was to drive the Spaniards from the West Coast, as that was the principal seat of their power. He accordingly sought the governorship of the province of Cuyo, which bordered on Chile, and repaired there to begin his real preparation. The _junta_, that governed Buenos Aires, gave him a small body of troops, which San Martin had already drilled and made effective soldiers. To these were added Chilean exiles, slaves who had been freed, and others whom he could gather at Mendoza, in the foothills of the Andes, which was his capitol. For two years he trained these men, gathered his artillery and ammunition and made his preparation to cross the passes of the Andes. No detail had been omitted by this careful organizer. To no one did he reveal his plans until he was ready for the start, then his army, which numbered about four thousand, was divided into two bodies, which proceeded through different passes across the border into Chile. More than seven thousand mules had been collected for the soldiers to ride, and every mule was shod. Specially designed sledges had been constructed on which to carry the guns. Jerked beef, parched corn and other supplies had been prepared for food in large quantities. The lonely and desolate passes of the mountains suddenly disgorged a well-equipped and disciplined army on Chilean soil. The royalist forces were taken by surprise, although reports had from time to time reached the commander. General Maroto concentrated his forces on the ridge of Chacabuco, whose yellowish-brown hills are almost devoid of vegetation. There was no definite road over this ridge, which consisted of an intricate complexity of steep-sided little valleys, or barrancas. General San Martin divided his forces, the command of one section being given to O’Higgins. Both sections attacked the Spanish forces vigorously, and the latter soon gave way through the very force of the onslaught.