An ethnic group of Madagascar that occupies the western edge of the island from Toliara in the south to Sambirano in the north. The term denominates a number of smaller ethnic groups that once comprised an empire, rather than an ethnic group in its own right. During the Middle Ages, their influence extended across the area that is now the provinces of Antsiranana, Mahajanga, and Toliara. However, with the domination of the Indian Ocean by the British fleet and the end of the Arab slave trade, they lost their power to the emerging Merina threat.