According to ethnohistorical traditions, the Desana and many of their Tukanoan neighbors are newcomers in the Vaupés territory where they arrived several generations ago, proceeding from the east by ascending the Rio Negro. Originally the Desana were band-level hunter-foragers. In the Vaupés area they first established contact with local sedentary Arawakan groups, from whom they learned manioc cultivation. Following some initial conjugal unions with nomadic Makú bands, the Desana began to intermarry with the endogamous Arawakan population. After overcoming mutual hostility and, following the transformation from uxorilocal residence and matriliny to virilocal residence and patriliny, the Desana and their Tukanoan neighbors assimilated, displaced most of the local Arawak, and established Tukanoan dominance in much of the Vaupés area. During the last decades of the nineteenth century, Brazilian-Italian missionary influence was strong on the upper Rio Negro but eventually weakened, to be renewed during the second decade of the twentieth century, when Dutch Catholic missionaries entered the Papurí. The rubber boom had little effect upon the Vaupés Indians, but recent political upheavals in Colombia, notably the cocaine trade, the discovery of gold mines, and the missionary activities of the Summer Institute of Linguistics (a Protestant organization), are threatening the cultural identity and survival of the Indians.