The Shilluk people (or Collo) belong to one of the Nilotic tribes of the Southern Sudan. Unlike the larger Nilotic groups, the Shilluk were not dispersed along the Nile but settled in a limited, uninterrupted area along the west bank of the Bahr al Jabal, near the tributary of the White Nile. They believed that the tribe was founded by the mythical being, Nyiking. They were traditionally ruled by a single politic-religious head called the Reth, who is the earthly representative of Nyiking on earth. The health of the Reth was believed to be closely related to the welfare of the tribe. Involved in the Sudanese civil war and inter-tribal rivalries of recent years, the Shilluk have felt increasingly marginalised with land taken by other tribes.