The last area claimed by Portugal in Africa was along the southeast coast on either side of the mouth of the Zambezi River. After reaching this area, known as the Swahili Coast, at the end of the 15th century, the Portuguese came to dominate most of it by the end of the 16th century. During the 17th century, they lost control of everything north of Cape Delgado to Arabs from Oman (who established the Sultanate of Zanzibar), leaving them with major ports at Mozambique, Quelimane, and Lourenço Marques, plus settlements along the Zambezi and other rivers.