It was believed until now that the Cree Indians were the aggressors Athapaskan groups from the second half of the eighteenth century and the early twentieth century. This paper, written from texts from published and archival records, rejects the first hypothesis and demonstrates that the Cree tribes formed the aboriginal population of the Churchill River Basin and were distributed to Lake Athabasca in the West. It is therefore the Chipewyan Indians, who at the time of the fur trade have invaded the territory of the Cree.