For ten thousand years, The Dalles served as a major center of commerce between the Pacific Coast and the inland Plateau. Chinook Indian traders negotiated exchange in Chinook jargon, a mixture of Salish, Nootka, Chinook, and eventually English. Trade goods from across the Northwest, Great Plains, Great Basin, and even Great Lakes regions could be found there, and scholars regarded the trade center at the Dalles as unmatched elsewhere in North America. By the late 1700s, goods supplied by European and American maritime fur traders were available at the Great Mart at the Dalles of the Columbia River. As Lewis and Clark approached, they saw the effects of European trade on local people, including scarlet and blue cloth, blankets, sailors jackets, a musket, sword, and brass kettles. This long prominence in exchange had produced a culture of skilled traders along the mid-Columbia, and annual trade gatherings had made Wishram, Wasco, and other Native people wealthy middlemen who controlled the flow of goods up and down the river. Lewis and Clark did not understand that the people of the Dalles were powerful businessmen who did not want to be challenged by foreigners, and the expedition's remaining trade goods were unimpressive to such wealthy people. When the captains complained about prices and acted impudently during slow trade, local people responded negatively. The expedition members became non-friends, trade shifted into competition for advantage rather than exchange of equal value, and those treated as non-friends were also considered trespassers on the local trade route, where a toll was expected and would be taken if it was not offered.