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. In 1498, Portuguese explorer Vasco da Gama became the first known European to reach the African Great Lakes coast; he stayed for 32 days. In 1505 the Portuguese captured the island of Zanzibar. Portuguese control lasted until the early eighteenth century, when Arabs from Oman established a foothold in the region. Assisted by Omani Arabs, the indigenous coastal dwellers succeeded in driving the Portuguese from the area north of the Ruvuma River by the early eighteenth century. Claiming the coastal strip, Omani Sultan Seyyid Said moved his capital to Zanzibar City in 1840. He focused on the island and developed trade routes that stretched as far as Lake Tanganyika and Central Africa. During this time, Zanzibar became the centre for the Indian Ocean slave trade. Due to the Arab and Persian domination at this later time, many Europeans misconstrued the nature of Swahili civilization as a product of Arab colonization. However, this misunderstanding has begun to dissipate over the past 40 years as Swahili civilization is becoming recognized as principally African in origin. Tanganyika (1850–1890) Tanganyika as a geographical and political entity did not take shape before the period of High Imperialism; its name only came into use after German East Africa was