In 1535 Almagro marched from Cuzco with five hundred Spaniards and ten thousand Indians, the latter under the command of a brother of the Emperor. After crossing the Titicaca basin, he surmounted the difficulties of the bleak and icy Puna, the snowy passes, and the Atacama desert, and descended finally into Chile. But he found the people poor and warlike, and encountered little gold. Returning in 1538 to make war on Pizarro, he was defeated and died strangled in prison by his relentless rival. Hernando and Gonzalo Pizarro, Francisco's brothers, became dominant on the Titicacan plateau, and began establishing great feudal lordships, dividing the country among their followers and exacting tribute and forced labour from the Indians. In 1540 the great Marquis himself visited Charcas, the southern capital and only large Indian city in Bolivia. Late that same year his quartermaster, Pedro de Valdivia, led another expedition along the route over the Bolivian plateau into northern Chile. Meanwhile the Spaniards were diligently searching Bolivia for the Indian gold mines. Though the Incas were known to have extracted immense quantities of the metal from the placers around Lake Titicaca, the surface deposits had been pretty well exhausted, and the Spaniards were disappointed. Silver, however, existed in abundance and the strangers began to work the mines shortly after they reached the plateau. About 1545 the great deposits of Potosi were discovered on a bleak mountainside four hundred miles south-east of Titicaca and near Charcas, in the regions where Gonzalo Pizarro possessed immense estates. At that time Gonzalo was virtually independent monarch of the whole Inca empire, having headed a successful revolt against a viceroy sent out to reorganise the country and put a stop to Indian slavery. But he did not long enjoy his riches, for in 1548 he risked his all in a hopeless battle with a new Spanish governor and ended his stormy life on the scaffold.