The Chewa or Cewa are a Bantu people of central and southern Africa and the largest ethnic group in Malawi. The Chewa are closely related to people in surrounding regions such as the Tumbuka and Nsenga. They are historically also related to the Bemba, with whom they share a similar origin in the Democratic Republic of the Congo. As with the Nsenga and Tumbuka, a considerable part of Chewa territory came under the influence of the Ngoni, who were of Zulu or Natal/Transvaal origin. An alternative name, often used interchangeably with Chewa, is Nyanja. Their language is called Chichewa. Internationally, the Chewa are mainly known for their masks and their secret societies, called Nyau, as well as their agricultural techniques. The Chewa (like the Nyanja, Tumbuka, Senga, Nsenga, Mang’anja) are a remnant of the Maravi (Malawi) people or empire. There are two large Chewa clans, the Phiri and the Banda, with a population of 1.5 million people. The Phiri are associated with the kings and aristocracy, the Banda with healers and mystics.