For centuries, the Nuba mountains of central Sudan have provided refuge for those fleeing from the strife of the plains and deserts of East Africa below. The Nuba peoples, proud and primitive, naked but for their beads and lip-plugs, exerted a curious fascination for the whites who followed in the tracks of the first colonialists. As late as the 1970s, the former Nazi filmmaker Leni Riefenstahl portrayed Nubian warriors as "black Aryans" in controversial photographs that recalled her work under Hitler.
The Nuba are at their lowest ebb, however. This week an assessment mission by western aid agencies, the first to be given access to this remote region, is expected to find evidence of mass starvation and gross human rights violations.
According to Mr Paul Murphy, an Irish aid volunteer with Concern who has spent the past year in the mountains, the Nuba have been caught on the faultline in the civil war between the Islamic government in the North and rebels in Southern Sudan. Frustrated by rebel advances, the Khartoum government has used hunger as a "lethal weapon," he says.
Thousands have been spirited away into so-called "peace camps" and reports of rape and other violations are widespread. Mere children are sold as slaves or conscripted into the government's army.
The catastrophe unfolding in the Nuba mountains is being repeated in at least two other regions of Southern Sudan. Instead of planting their crops, farmers are fleeing from one or other of the ravaging armies in the region. The rains are coming, but the fields have not been planted.
They call them "complex emergencies" in the aid business, a handy euphemism that generally boils down to trying to feed starving people while dodging the bullets of rival armies. But even by African standards, the disaster in Southern Sudan is complex. In broad terms, the civil war pits the Islamic North against the Christian and animist South. From its stronghold in Khartoum, the government sends out fighter jets to bomb a variety of rebel forces operating in a vast, empty country half the size of the United States.
Within this pattern, though, lies an ever-changing constellation of alliances, of shifting battle-lines and allegiances, coupled with a rough equality of human rights abuses and terror on both sides.
Fifteen years of such a civil war, and two consecutive years of crop failure, have brought the region to the brink of starvation. Half a million people are in immediate need of assistance, according to the UN. And the situation is getting worse, with up to 2.5 million facing starvation in the coming months.
Not for the first time, the problem has thrown the international aid agencies into a quandary. For months, they have been gathering evidence of a growing calamity - crop failure, widespread malnutrition, disease - yet their collective response has been muted.
There are two reasons for this. In February the Khartoum government banned relief flights into the worst-affected Bahr el Ghazal and Lakes regions, while continuing to bomb civilians. There was no point in sounding the alarm bells, and raising large amounts of money, if the aid could not be delivered to those who need it.
Under international pressure, Khartoum has relented and last week agreed to allow four relief flights daily. But there is a second reason which, tragically, sees the survival of ordinary Africans hang from the thread of western whims. In these days of short attention spans and "compassion fatigue", the agencies know they have only one shot at gaining the world's attention.
Confronted with pictures of starving Sudanese, the West's television-viewers are likely to shed a tear and open their cheque-books. But a mistimed appeal or a crisis that stretches out is likely to have the viewers reaching for their remote controls.
Aid agencies have also to decide how best to further their humanitarian interests - whether to "get into bed" with the main rebel force, the Sudan People's Liberation Army, or to delicately balance between the SPLA and the government in distant Khartoum. The crisis highlights the need for political and even military interventions to accompany humanitarian work.
Most agencies have been down this road before and know that in 1993, for example, most of the food aid airlifted into the country ended up in the hands of pillaging armies. Today's soldiers are just as hungry.
Reuters adds: Sudanese rebels said yesterday they killed four government soldiers during an ambush on an army convoy, their second attack since Thursday.