After expelling their European rivals from the Amazon in the early–seventeenth century, the Portuguese set about exploiting the principal assets of the vast basin—the indigenous inhabitants. As allies, converts, and slaves the native population provided the labor and much of the social fabric of the developing colony. While a variety of canoe-borne expeditions ventured ever farther up the main river and its tributaries seeking elusive gold, harvesting forest products, and expanding the crown's domain, prosperity and power for the leaders and sponsors of those forays derived mainly from the human cargo brought downstream to missions, forts, and other settlements. As a result, crown and colonial authorities attempted to regulate and control the expeditions, and fierce competition developed among institutions and individuals involved in the process. Documents in Portuguese and Brazilian archives reveal the key role played by the Indians themselves in collaboration with the little-studied cross-cultural intermediaries, known as cunhamenas.