The lack of formal authority was filled in the 1850s by a set of powerful merchant princes. In the east Muhammad Ahmad al-Aqqad controlled much land, but the most powerful was Al-Zubayr Rahma Mansur who came to control the Bahr el Ghazal and other parts of South Sudan. Al-Zubayr was a merchant from Khartoum, who hired his own private army and marched south.

He set up a network of trading forts known as "zaribas" through the region, and from these forts controlled local trade. The most valuable commodity was ivory. In previous centuries Sudanese merchants had not placed a high price on ivory, but the period of Egyptian rule coincided with a great increase in global demand as middle class Americans and Europeans began to purchase pianos and billiard balls.

To manage the trade al-Zubayr needed labour, and thus also began to capture a significant number of slaves. To his mercenary force, he also conscripted a large slave army. Due to trade disputes with the Sultanate of Darfur al-Zubayr went to war against that kingdom and in 1874 defeated their forces and killed Ibrahim, the last Fur Sultan.

First civil war
Rebellions
Al-Zubayr's trading empire
Tribal conflict