The ancient history of the Kongo people has been difficult to ascertain. The region is close to East Africa, considered to be a key to the prehistoric human migrations. This geographical proximity, states Jan Vansina, suggests that the Congo river region, home of the Kongo people, was populated thousands of years ago. Ancient archeological evidence linked to Kongo people has not been found, and glottochronology – or the estimation of ethnic group chronologies based on language evolution – has been applied to the Kongo. Based on this, it is likely the Kongo language and Gabon-Congo language split about 950 BCE.