Piecing together information collected from informants among Caribou Inuit as well as from scattered written sources, this paper unravels the precise nature of interaction between these Inuit from the West Coast of Hudson Bay and their remote neighbours, the Copper Inuit settled on the Arctic Coast and Victoria Island. These relationships are examined in their historical and ethnological context. Commercial exchanges, initiated or stimulated through the support of the Hudson's Bay Company (HBC) at the beginning of the XXth century, were carried out by middlemen who travelled very long distances. This led to immigration and assimilation of Copper Inuit among Caribou Inuit. Contacts came to a halt around 1925: Caribou Inuit had been severely hit by famines, whereas Copper Inuit were just beginning to trade at posts recently established on their territory. The case under study in this paper shows 1) that individuals play a crucial role in bringing into contact different populations and, 2) that changes induced go far beyond the commercial sphere. The paper also touches on the theories concerning the origin of the Caribou Inuit in the light of these new data.