The Chilean aristocracy could not resist this temptation to make their country the dominant power on the Pacific coast, and without any warning their ships sailed up from Valparaiso and captured the Peruvian fleet at Callao. This left the way clear to land troops on the Bolivian or Peruvian coasts. The first expedition went against the province of Arequipa. It landed without resistance and climbed to the city, while Santa Cruz's army maintained a defensive attitude. Lack of provisions soon compelled the Chilean general to promise that the war should not be renewed if he were allowed to depart. His government refused to ratify this agreement, and sent another expedition to the neighbourhood of Lima, which was accompanied by Gamarra and a large number of Peruvian exiles. Orbegoso declared his independence of Santa Cruz and gave battle to the Chileans on his own responsibility, but was defeated and fled to Guayaquil. A year elapsed before Santa Cruz could march an adequate army to the neighbourhood of Lima. As he approached, Gamarra and the Chileans evacuated the capital, retiring up the coast, whither the Bolivians followed. Repulsed in an attack on the rearguard of the fleeing allies, and feeling that he could not rely upon the Peruvians in his army, he took the defensive and posted his forces near the town of Yungay, occupying a hill called the Sugar Loaf. The allies stormed this hill by a brilliant assault in which they suffered greatly, but their unexpected success completely demoralised Santa Cruz's army. His men scattered in all directions, and though he escaped with his life, his prestige was destroyed. Gamarra became president of Peru, Bolivia revolted, and Santa Cruz made his way to a European exile. During two years Gamarra kept his turbulent rivals in check, but he then rashly undertook a campaign against Bolivia, giving as a pretext the refusal of its government to expel the old adherents of Santa Cruz. The Peruvian army advanced into Bolivian territory, only to be overthrown in the bloody battle of Yngavi. Gamarra was killed and his best officers taken prisoners. The Bolivians made a counter-invasion, but a treaty of peace was soon signed. The removal of the common danger was the starting signal for a race to power among the Peruvian generals. Each of them had raised troops on his own account and now proposed to use them for his own benefit. They ignored the claims of Gamarra's constitutional successor. La Fuente, Vivanco, and Vidal formed an alliance and proclaimed the latter dictator; Torico seized Lima and declared himself supreme chief; Vidal hastened down from Guamanga and defeated him; then Vivanco rebelled against Vidal and in his turn descended on the capital.