The Sea of Zanj was a former name for the region of the western Indian Ocean next to the African Great Lakes known as Zanj by medieval Arab geographers. Arab mariners feared the Sea of Zanj, and rumors about dangers in the waters abounded, particularly towards its far southern boundaries. Ancient Muslim travelers and chroniclers such as Al Masudi and Ibn Batuta used the term to describe the sea expanses near the eastern portion of the African continent. Although physically undefined, the Sea of Zanj encompassed a large marine expanse spanning nearly as far as ancient navigators could go on their dhows. The Sea of Zanj was positioned to the south of the Erythraean Sea, subject to Monsoon wind changes. It extended from the coast of Southeast Africa to the Mozambique Channel, including the Comoros and the waters off Madagascar’s eastern coast.