One of nineteenth-century North America’s most consequential international events took place during the hot summer of 1840, on the Arkansas River. Representatives of half a dozen sovereign nations met for a summit to bury old grievances and commit to a future of peace and commerce. Over the next several days, thousands of men, women, and children arrived to celebrate the diplomatic breakthrough, settling into noisy, joyful camps for miles along a wide bottom of the Arkansas. Southern Cheyennes and Arapahos waded south across the river to accept hundreds of horses as presents from their former enemies. The next morning Kiowas, Kiowa Apaches, Yamparikas, and Kotsotekas (two of the four nations of the Comanche confederacy) made the trip in reverse to receive guns, ammunition, and other coveted manufactured goods. Dignitaries sat down to a meal sweetened with molasses from New Orleans and reflected on the dividends of their diplomacy.