Murad and his counsellors solved the problem of assimilation by sanctioning the reduction of captives to slavery, and by creating the corps of janissaries. A law was promulgated which gave to the Osmanli soldier absolute right to the possession of prisoners, unless they consented to profess and practise Islam. Prisoners were regarded as booty. They could be kept for domestic or agricultural labour, or sold in the open market, subject to the government’s equity of one in five. The disgrace, even more than the hardships, of slavery was so keenly felt by the Greeks[259] that many for whom there was no other way preferred a change of religion to loss of freedom. The right to make slaves of prisoners was efficacious in providing wives and concubines for the conquerors, who were practically without women of their own. The widows of the fallen, and the daughters of Greeks, Serbians, and Bulgarians, became the instruments of increasing the Ottoman race. In the hundred years from Murad I to Mohammed II, the Osmanlis became in blood the most cosmopolitan and vigorous race the world had known since the days of the Greeks and Romans. Greek, Turkish, Serbian, Bulgarian, Albanian, Armenian, Wallachian, Hungarian, German, Italian, Russian, Tartar, Mongol, Circassian, Georgian, Persian, Syrian, and Arabian--this was the ancestry of the Osmanlis who, under Soleiman the Magnificent, made the whole world tremble. In richness of blood the only parallel to the Osmanlis in modern times is the present population of the United States and Canada. But this indirect method of conversion as an alternative to slavery did not immediately increase the masculine element among the Osmanlis. In a city taken by assault the more virile portion of the male population was killed off, and those who remained were able to buy life and freedom. Male slaves were an embarrassment to the ever-moving armies of Murad. Ransom money was welcomed by the captors. In many cities the inhabitants surrendered without a struggle, and were secured in their freedom by the terms of capitulation. In rural districts the threat of slavery was little felt. The Osmanlis had neither time nor strength to put out the drag-net. Everywhere in the Balkans refuge in the mountains is easy. Then, too, the loss of cultivators would have made the highly prized timarets worthless, and would have caused a famine in foodstuffs or a diminution of taxes on harvests. Another means of bringing pressure to bear upon the Christians had to be devised.