There was also the Indian Chamber of Commerce, the so-called Casa de Contratacion, which was intrusted with the supervision of the West Indian trade. This body saw to the provision of ships, received all goods, and had jurisdiction of all commercial questions between the colonies and the home country. Through the “Casa” passed all the enormous mineral wealth that came from the opening up of the mines on the continent of America. In 1515, owing to the representations made in Spain by Las Casas of the grievances of the native population, Cardinal Ximenes sent three friars of the order of St. Jerome with full authority to act on behalf of the Indians. Las Casas was appointed protector. When the commission was under discussion, he asked specifically for unconditional liberty for the natives and for the suppression of the serf system in all its forms and provisions, in order to enable the European proprietors to work their estates profitably. These humanitarian efforts had little effect in arresting the prevailing methods of exploitation. When the pearl coast near Trinidad in the northeastern region of South America attracted settlers, there was a fresh demand for enforced labor of a new type, and the native tribes were raided in order to secure supplies of pearl divers. Although through the voyages of explorers various widely separated points on the mainland had been touched, no place had been effectively occupied by settlement. Wherever efforts were made, the native population, the Caribs, were found to have such warlike qualities that no successful foothold could be secured. The climate also proved fatal to Europeans. After Balboa made his celebrated passage across the Isthmus, an expedition of 15 ships and 2000 men came to occupy the land, but 600 of these died in a few months. No point yet visited by European adventurers had offered examples of native civilization higher than the primitive standards attained by the Carib and the Arawak. But in the interior, in the thick forests of Central America, were scattered about the relics of an ancient culture. In a triangular space including some of northern Yucatan, Mitla in Oaxaca, and Copan in Honduras, there are the remains of sixty communities distinguished by temples, tombs, statues, bas reliefs, fragments of buildings, and deserted palaces. These are relics of a race who at the discovery of America had lost their supremacy for many generations. According to some reckonings, at least as early as the twelfth century these celebrated dead cities were founded.