Reaching back about 10,000 years, Tanzania is believed to have been populated by hunter-gatherer communities, probably Khoisan speaking people. Between three and six thousand years ago, they were joined by Cushitic-speaking people who came from the north, into which the Khoisan peoples were slowly absorbed. Cushitic peoples introduced basic techniques of agriculture, food production, and later, cattle farming.[2]

Travellers and merchants from the Persian Gulf and Western India have visited the East African coast since early in the first millennium CE. Greek texts such as the Periplus of the Erythraean Sea and Ptolomey's Geography list a string of market places (emporia) along the coast. Finds of Roman-era coins along the coast confirm the existence of trade, and Ptolomey's Geography refers to a town of Rhapta as "metropolis" of a political entity called Azania. Archaeologists have not yet succeeded in identifying the location of Rhapta, though many believe it lies deeply buried in the silt of the delta of the Rufiji River. A long documentary silence follows these ancient texts, and it is not until Arab geographical treatises were written about the coast that our information resumes.

Remains of those towns' material culture demonstrate that they arose from indigenous roots, not from foreign settlement. And the language that was spoken in them, Swahili (now Tanzania's national language), is a member of the Bantu language family that spread from the northern Kenya coast well before significant Arab presence was felt in the region. By the beginning of the second millennium CE the Swahili towns conducted a thriving trade that linked Africans in the interior with trade partners throughout the Indian Ocean. From c. 1200 to 1500 CE, the town of Kilwa, on Tanzania's southern coast, was perhaps the wealthiest and most powerful of these towns, presiding over what some scholars consider the "golden age" of Swahili civilization. In the early 14th century, Ibn Battuta, a Berber traveller from North Africa, visited Kilwa and proclaimed it one of the best cities in the world. Islam was practised on the Swahili coast as early as the eighth or ninth century CE.[4]
