We should bear in mind that they had not long been converted to Christianity when the Moslems came upon them. The religion of Christ had no very strong hold over them. The consequence was that, when they found that their conquerors would let them live far more comfortably in the country if they adopted the religion of Mahomet, there were many who were quite willing to do so. The conquerors do not seem to have used their power cruelly, and it is likely that the people in general were in quite as good a position and quite as happy under the new rule as under the old. The Jews, particularly, of which nation there were very many in Spain, were almost certainly happier, for the Christian government had persecuted and oppressed them and the Moslems were far more tolerant. The Moslems, indeed, whether in Spain or Asia, or even in Africa, were probably quite as advanced in general culture as the Christians. Europe was indebted to them for a better knowledge of medicine than the Western world had acquired before. The game of chess was given us {177} by them, and when we say "check-mate" we are really saying "Sheik mat"=the sheik, or king, is dead. By the tenth century the Christian power from the north was beginning to press heavily upon the Mahommedans in the south, and this pressure southward led to the foundation of the Kingdom of Castile, in the centre of Spain. Another kingdom which had been independent, that of Leon, was absorbed by Castile. This name of Castile is said to be derived from _castillas_, or castles, because the Christians, as they spread southwards, made forts or castles, as they went, which they held as outposts against the Mahommedans. All through the next, the eleventh century, in the course of which William the Conqueror came to Britain, the war between Christian and Moslem went on, a continual Crusade, in Spain. We may notice that twice, when the Moslems were hard pressed, they summoned others of their own creed in Africa to come to their assistance. On each occasion of the coming of these new forces the Christians were forced back. [Sidenote: Waning power of the Moors] But the energy and the organisation which made the strength of these counter-attacks seem to have spent themselves quickly. Always there was more unity among the Christians and a more steady purpose. They came on again to the attack and found the Moslem force less able to resist. A very important gain for the Christians was the taking of Cordova by Ferdinand III., King of Castile and Leon, in 1236. Cordova was the chief city of Mahommedan Spain. There was a Caliph, or head of the Moslem Church, at Cordova, independent of the Caliph at Mecca. It is rather like the position of the Pope at Rome and the Patriarch at Constantinople in the Christian Church at that time.