AMONGST THE NUMEROUS NOMAD RACES of Central Asia there were two great tribes - the Mongols and the Turks - who in the thirteenth century overran a great part of the Muslim empire and penetrated beyond it. Hulagu Khan captured Baghdad, the seat of the renowned Abbasid Khalifate and the Mongols soon overran the Syrian empire of Saladin, which had come now under the rule of the Mamluk Sultans of Egypt. The Mongols on different occasions made several ineffectual attempts to invade Egypt, and were repulsed by the bravery of the Mamluks; but they entered Europe and advanced as far as Hungary. They were nomads and, as a rule, could not settle down; so after ravaging a country they usually retired from it. For a time, however, they retained possessions in China, and, as the Golden Horde, ruled in the Crimea; but they left no permanent mark on the Muslim empire of the Khalifate; and so we may pass them by.