And as he came so he flew away again, mysteriously and incomprehensibly. Again and again he lost his armed force. In some districts he closed the paths leading to wells in order to bring the refractory tribes to submission. With inflexible severity he broke the power of the chiefs who still carried on trade in slaves. He freed numbers of black captives and drilled them as soldiers, for his own fighting men were the scum of Egypt and Syria. With a handful of men he dealt his blows at the weakest points of the enemy's defence and thus always gained the victory. In four months he suppressed the revolt and checked the power of the slave-dealers. Gordon had now cleared all the west of the Sudan, and only Dara in southern Darfur remained to be dealt with. There the most powerful slave-dealers had collected to offer resistance. He came down one day like lightning into their camp. They might easily have killed him--it was he who had ruined their trade in black ivory. He went unconcernedly among the tents, and they did not dare to touch him. And when his own troops arrived, he summoned all the chiefs to his tent and laid his conditions before them. They were to lay down their arms and be off each to his own home; and one by one they obeyed and went away without a word. But the slave-trade was a weed too deeply rooted in the soil to be eradicated in a single day, and the revolt and troubles which constantly arose out of this horrible traffic gave Gordon no peace. He left the Sudan at the end of 1879, and the next two years were occupied with work in India, China, Mauritius, and South Africa. Meanwhile remarkable events had occurred in Egypt. Great Britain had sent vessels and troops to the land of the Khedive, and had taken over the command and the responsibility. The chief of the dervishes, Mohamed Ahmed, whom we remember on the small island in the Nile, proclaimed that he was chosen by God to relieve the oppressed, that he was the Mahdi or Messiah of Islam. Discontent prevailed among the Mohammedans throughout the Sudan, for Egypt had at length prohibited the slave-trade, and the Mahdi collected all the discontented people and tribes under his banner. His aim was to throw off the yoke of Egypt. Proud and arrogant, he sent despatches through the whole of the Sudan, and his summons to a holy war flew like a prairie fire over North Africa. The British Government, which was now responsible for Egypt, was in a difficulty. The Sudan must either be conquered or evacuated, for the Egyptian garrisons were still at Khartum and at several places even down to the equator. The Government decided on evacuation, and Gordon was sent to perform the task of withdrawing all the garrisons. He accepted the mission and set out immediately for Cairo.