Early "Proto-Cossack" groups are generally reported to have come into existence within the present-day Ukraine in the 13th century as the influence of Cumans grew weaker, although some have ascribed their origins to as early as the mid-8th century. Some historians suggest that the Cossack people were of mixed ethnic origin, descending from Russians, Ukrainians, Belarusians, Turks, Tatars, and others who settled or passed through the vast Steppe. Some Turkologists, however, argue that Cossacks are descendants of the native Cumans of Ukraine, who had lived there long before the Mongol invasion.