<P> One theory is that it was pressure from the Shilluk that drove the Funj people north, who would establish the Sultanate of Sennar . The Dinka remained in the Sudd area, maintaining their transhumance economy . </P> <P> While the Dinka were protected and isolated from their neighbours, the Shilluk were more involved in international affairs . The Shilluk controlled the west bank of the White Nile, but the other side was controlled by the Funj Sultanate, and there were regular conflict between the two . The Shilluk had the ability to quickly raid outside areas by war canoe, and had control of the waters of the Nile . The Funj had a standing army of armoured cavalry, and this force allowed them to dominated the plains of the sahel . </P> <P> Shilluk traditions tell of King Odak Ocollo who ruled c. 1630 and led them in a three decade war with Sennar over control of the White Nile trade routes . The Shilluk allied with the Sultanate of Darfur and the Kingdom of Takali against the Funj, but the capitulation of Takali ended the war in the Funj's favour . In the later 17th century the Shilluk and Funj allied against the Jieng, a group of Dinka who rose to power in the border area between the Funj and Shilluk . The Shilluk political structure gradually centralized under the a king or reth . The most important is Reth Tugo who ruled c. 1690 to 1710 and established the Shilluk capital of Fashoda . The same period saw the gradual collapse of the Funj sultanate, leaving the Shilluk in complete control of the White Nile and its trade routes . The Shilluk military power was based on control of the river . </P> <P> The non-Nilotic Azande people, who entered southern Sudan in the 16th century, established the region's largest state . The Azande are the third largest nationality in Southern Sudan . They are found in Maridi, Iba, Yambio, Nzara, Ezon, Tambura and Nagere Counties in the tropical rain forest belt of western Equatoria and Bahr el Ghazal . In the 18th century, the Avungara people entered and quickly imposed their authority over the Azande . Avungara power remained largely unchallenged until the arrival of the British at the end of the 19th century . </P>

Factors that contributed to nilotic migration into kenya