In 1441 negro slaves had been brought home by the explorer Nuno Tristão, and the slave trade steadily increased as years went on, till by far the greater part of Southern Portugal was cultivated for the nobles by black labour. It was cheap, but it drove out the peasantry for lack of employment, and led to more emigration than would otherwise have been the case. Then came King Emanuel’s great mistake, the expulsion of the Jews. All Jews who refused to become Christians were ordered to leave the country within six months. A great many of them were well known for their honesty, industry, and wealth, and also for their high intellectual qualities, so that Portugal was in reality banishing vast numbers of her most capable and enterprising citizens. In 1536, John III. introduced the Inquisition, which in course of time became so fanatical that the merest suggestion of heresy caused men and women to be imprisoned, cruelly tortured, and even burnt at the stake. All this tended still further to crush out the manhood of the people. Moreover, the powers of the Inquisition were largely used for political purposes. Thus, under a fair exterior, the country was steadily decaying. King John died, and in 1557 we once more find a little child of three years old--Dom Sebastian--ascending the throne. This time, however, there was no wise mother to act as Regent, and at fifteen the young King was declared of age, and took the government into his own hands. He was by nature a dreamer and a visionary, and very obstinate. He looked on war as the noblest occupation for a King, and being deeply religious, became fired with a romantic ambition to become a true soldier of the Cross, and to carry Christianity to the Moors in the North of Africa at the point of the sword. The Pope and the King of Spain both refused to help in such a wild undertaking; Sebastian’s own Ministers and advisers did their best to dissuade him, but he was a despotic and self-willed monarch, and in his saintly enthusiasm he drained his treasury and imposed new taxes on his already heavily burdened people, to provide money for the great Crusade. His best Generals and fighting men were all in India, but he raised an army of raw recruits and mercenaries hired from other countries, and at length set sail for Morocco with an army of about 17,000 men. Poor Dom Sebastian was utterly unpractical, and a hopelessly bad General, but he proved himself, in his first and last great battle, to be a brave and fearless soldier. His little army was surrounded by that of the Moorish “Sherĩf,” more than three times its numbers, and after an heroic struggle, in which quite half the force lost their lives, the remnant were taken prisoners.