Tanzania has a long history of human habitation some of the earliest hominoid fossils in the world were discovered in Olduvai Gorge and show records of hominoid habitation in the region going back at least 3 million years. It is thought that early hunter-gatherer communities inhabited the northern highlands as far back as 10,000 years ago and remained largely isolated until the arrival of Cushitic-speaking tribes from the north, who brought basic agricultural technologies to the area between 3,000 and 5,000 years ago.
More recent migrations of Bantu-speaking tribes from western Africa began around 1000 BC, and with their assimilation came advances in iron and steel production. Ancestors of the Masaai arrived more recently, beginning their migration around the 15th century and continuing to arrive from the area around southern Sudan for another three hundred years. Battles over grazing and agricultural land began as ethnic groups consolidated and appropriated loose borders and tribal regions.