Bantu-speaking peoples who founded tribes during the Bantu expansions largely displaced and absorbed the earliest inhabitants of the region, the Pygmy people, about 1500 BC. The Bakongo, a Bantu ethnic group that also occupied parts of present-day Angola, Gabon, and Democratic Republic of the Congo, formed the basis for ethnic affinities and rivalries among those countries. Several Bantu kingdoms—notably those of the Kongo, the Loango, and the Teke—built trade links leading into the Congo River basin.
If it is possible to answer this question, answer it for me (else, reply "unanswerable"): What group of people were living in the area that would become the Congo prior to the arrival of Bantu tribes?
Pygmy