Pygmies probably once lived in the continental region that is now Equatorial Guinea, but are today found only in isolated pockets in southern Río Muni. Bantu migrations started probably around 2,000 BC from between south-east Nigeria and north-west Cameroon (the Grassfields). They must have settled continental Equatorial Guinea around 500 BC at the latest. The earliest settlements on Bioko Island are dated to AD 530. The Annobón population, originally native to Angola, was introduced by the Portuguese via São Tomé island.