Geographically, Dar Fertit is the country south of Darfur and east of the highlands in modern eastern Central African Republic, where tributaries of the White Nile begin their long journey toward the Sudd. The region includes parts of southwestern Sudan and northwestern South Sudan. The terrain is inhospitable: thorn scrub and seasonal wetlands, impassable during the rains from May to October, searing through the dry months. In the 1800s, people from further west and north fled here to escape the slave raids. That layering - refugees on top of older populations, each bringing their own languages and lineages and rituals - is why Dar Fertit has never been a single polity. It has always been a patchwork.

In the present era, 'Fertit' is the catch-all word used in Western Bahr el Ghazal, South Sudan, for groups and peoples who are not Dinka, not Arab, not Luo, not Fur. The label lumps together populations who often speak mutually unintelligible languages - Kresh, Yulu, Banda, Binga, and others - and who historically fought each other as much as they coexisted. What has made them increasingly unified, over the past half-century, is not internal affinity but external pressure. The Dinka, the largest ethnic group in South Sudan, expanded into areas the Fertit peoples consider ancestral. Fertit political organizing from the 1980s onward has centered on opposition to Dinka dominance in Western Bahr el Ghazal. The name forced on them by slavers has become, with complicated feelings, a name of solidarity.

As Egypt expanded up the White Nile in the middle of the nineteenth century - a period of Ottoman-Egyptian rule known locally as the Turkiyah - it granted concessions to private merchants to gather ivory and enslaved people. These merchants built fortified trading camps called zaribas, palisades of thorn bush enclosing compounds of huts, storage sheds, holding pens for captives, corrals for cattle. The zariba merchants raided the surrounding country, then sold what they took to the Egyptian state or to private buyers downstream. One of these merchant-warlords, al-Zubayr, became the most powerful figure in the region in the mid-1800s. He conquered Dar Fertit outright and made it his personal domain. His main zariba, Deim Zubeir (Zubayr's Camp), was the nucleus of the modern town of the same name in Western Bahr el Ghazal. Egypt eventually annexed the region in 1873. The slave trade did not end with annexation. It changed administrators.

Today's Dar Fertit lies mostly in the western part of Raga County - pronounced 'raja' - in Western Bahr el Ghazal, with Fertit communities also in northwestern Western Equatoria and the northwesternmost corner of Northern Bahr el Ghazal. Raga was the end of the road for many things, and the beginning of the road for others. Colonial maps show it as a market town, a terminus for trading routes coming down from Darfur. The Catholic missions arrived in the mid-twentieth century. The Second Sudanese Civil War devastated the area from 1983 onward - the SPLA came, the government came, the militias came, the refugees came and went and came again. Independence in 2011 did not erase any of that, but it opened the possibility of something different.

What makes Dar Fertit remarkable is how a category imposed by outsiders, for the purpose of enslaving people, has become something like a shared identity among the descendants of those same people. This is not a clean story. It carries the weight of every caravan, every raid, every burning village, every chain and every blade. But to call yourself Fertit now, in Wau or Raga or Juba, is to claim a lineage that the sultanates tried to erase and the Egyptians tried to own. The languages are still different. The villages still remember their own specific histories. And yet the word, once a sentence, has become a banner. The people who were supposed to disappear are still here, still speaking their own tongues, still naming their own children, still living on the lowlands that the map calls Dar Fertit.