Mombasa modern period, Mombasa was a key node in the complex and far reaching Indian Ocean trading networks, its key exports then were ivory, millet, sesamum and coconuts. In the late pre-colonial period (late 19th century), it was the metropolis of a plantation society, which became dependent on slave labour (sources contradict whether the city was ever an important place for exporting slaves) but ivory caravans remained a major source of economic prosperity. Mombasa became the major port city of pre-colonial Kenya in the Middle Ages and was used to trade with other African port cities, the Persian Empire, the Arabian
Mombasa Peninsula, the Indian Subcontinent and China. 16th-century Portuguese voyager Duarte Barbosa claimed, "[Mombasa] is a place of great traffic and has a good harbour in which there are always moored small craft of many kinds and also great ships, both of which are bound from Sofala and others which come from Cambay and Melinde and others which sail to the island of Zanzibar." Vasco da Gama was the first known European to visit Mombasa, receiving a chilly reception in 1498. Two years later, the town was sacked by the Portuguese. In 1502, the sultanate became independent from Kilwa Kisiwani and