Zanj (Arabic: زَنْج, adj. زنجي, Zanjī; Persian: زنگی, romanized: Zangi)[1][2] was a name used by medieval Muslim geographers to refer to both a certain portion of Southeast Africa (primarily the Swahili Coast) and to its Bantu inhabitants.[3] This word is also the origin of the place-names Zanzibar ("coast of the Zanji") and the Sea of Zanj.

The latinization Zingium serves as an archaic name for the coastal area in modern Kenya and Tanzania in southern East Africa. The architecture of these commercial urban settlements are now a subject of study for urban planning.[4][5] For centuries the coastal settlements were a source of ivory, gold, and slaves, from sections of the conquered hinterland, to the Indian Ocean world.[6]

Zanj in Arabic means the "country of the blacks". Other transliterations include Zenj, Zinj, and Zang.[7][8] Anthony Christie argued that the word zanj or zang may not be Arabic in origin: a Chinese form (僧祇 sēngqí) is recorded as early as 607 AD. Christie argued that the word is South East Asian in origin.[9]: 33  The Javanese word jenggi means African people, specifically the people of Zanzibar.[10]: 740 

It is known that the Indonesian Austronesian peoples reached Madagascar by ca. 50–500 CE.[11][12] As for their route, one possibility is that the Indonesian Austronesians came directly across the Indian Ocean from Java to Madagascar. It is likely that they went through the Maldives, where evidence of old Indonesian boat design and fishing technology persists until the present.[13][9]: 32 

Geographers historically divided the eastern coast of Africa at large into several regions based on each region's respective inhabitants. Arab and Chinese sources referred to the general area that was located to the south of Misr (Egypt), Al-Habasha (Abyssinia) and Barbara (Somalia) as Zanj.[14]

Zanj was situated in the Southeast Africa vicinity and was inhabited by Somalians and Bantu-speaking peoples called the Zanj.[3][14][15] The core area of Zanj occupation stretched from the territory south of present-day Ras Kamboni[16] to Pemba Island in Tanzania. South of Pemba lay Sofala in modern Mozambique, the northern boundary of which may have been Pangani. Beyond Sofala was the obscure realm of Waq-Waq, also in Mozambique.[17][18] The 10th-century Arab historian and geographer Abu al-Hasan 'Alī al-Mas'ūdī describes Sofala as the furthest limit of Zanj settlement, and mentions its king's title as Mfalme, a Bantu word.[3]