Whatever it did for the balance of payments, oil did not bring peace. Sudan, Africa 's largest country by geography and one of its poorest, has been battered by civil war for thirty seven of the forty seven years since the British left. The government - military or elected, Islamist or secular - has always belonged to a minority population , the educated Arab-speaking Muslim elite from the northern Nile Valley. Sudan's thirty five million population - sixty to seventy percent African and thirty to forty percent non-Muslim - was economically, socially, and politically marginalised.