The elements in the problem were simple. There was the flood of Arabs pouring out of Arabia and bearing everything down in their course. These must be retained as a conquering instrument if Islam were to exist. Thus they must be prevented from settling down on the rich lands they had seized,—from becoming agriculturists, merchants, and so on, and so losing their identity among other peoples. The whole Arab stock must be preserved as a warrior caste to fight the battles of God. This was secured by a regulation that no new lands should be held by a Muslim. When a country was conquered, the land was left to its previous possessors with the duty of paying a high rent to the Muslim state and, besides, of furnishing fodder and food, clothing and everything necessary to the Muslim camp that guarded them. These camps, or rather camp-cities, were scattered over the conquered countries and were practically settlements of Muslims _in partibus infidelium_. The duty of these Muslims was to be soldiers only. They were fed and clothed by the state, and the money paid into the public treasury, consisting of plunder or rents of conquered lands (_kharaj_), or the head-tax on all non-Muslims (_jizya_), was regularly divided among them and the other believers. If a non-Muslim embraced Islam, then he no longer paid the head-tax, but the land which he had previously held was divided among his former co-religionists, and they became responsible to the state. He, on the other hand, received his share of the public moneys as regularly distributed. Within Arabia itself, no non-Muslim was permitted to live. It was preserved, if we may use the expression, as a breeding-ground for defenders of the faith and as a sacred soil not to be polluted by the foot of an unbeliever. It will readily be seen what the results of such a system must have been. The entire Muslim people was retained as a gigantic fighting machine, and the conquered peoples were machines again to furnish it with what was needed. The system was communistic, but in favor of one special caste. The others—the conquered peoples—were crushed to the ground beneath their burdens. Yet they could not sell their land and leave the country; there was no one to buy it. The Muslims would not, and their fellow-co-religionists could not, for with it went the land-tax. [Sidenote: UTHMAN]