SUBJUGATION OF SPAIN BEGUN, 711 A.D. With North Africa in their hands the Moslems did not long delay the invasion of Spain. In 711 A.D. an army of Arabs and Berbers, under their leader Tarik, crossed the strait which still bears his name [13] and for the first time confronted the Germans. The Visigothic kingdom, [14] already much enfeebled, proved to be an easy prey. A single battle made the invaders masters of half of Spain. Within a few years their hosts swept northward to the Pyrenees. Only small districts in the northern part of the Spanish peninsula remained unconquered. THE MOSLEM ADVANCE IN GAUL The Moslems were not stopped by the Pyrenees. Crossing these mountains, they captured many of the old Roman cities in the south of Gaul and then advanced to the north, attracted, apparently, by the booty to be found in Christian monasteries and churches. In the vicinity of Tours they encountered the great army which Charles Martel, the chief minister of the Frankish king, [15] had collected to oppose their advance. BATTLE OF TOURS, 732 A.D. The battle of Tours seems to have continued for several days. Of its details we know nothing, though a Spanish chronicler tells us that the heavy infantry of the Franks stood "immovable as a wall, inflexible as a block of ice" against the desperate assaults of the Moslem horsemen. When the Franks, after the last day's fighting, wished to renew the struggle, they found that the enemy had fled, leaving a camp filled with the spoils of war. This engagement, though famous in history, was scarcely decisive. For some time afterward the Moslems maintained themselves in southern Gaul. It was the Frankish ruler, Pepin the Short, who annexed their possessions there and drove them back across the Pyrenees to Spain. [16] 135. THE CALIPHATE AND ITS DISRUPTION, 632-1058 A.D. THE FOUR "ORTHODOX" CALIPHS, 632-661 A.D. Only eighteen years after the battle of Tours, the Arabian Empire was divided into two rival and more or less hostile parts, which came to be called the Eastern and Western caliphates. The title of caliph, meaning "successor" or "representative," had first been assumed by Mohammed's father-in-law, Abu Bekr, who was chosen to succeed the prophet as the civil and religious head of the Moslem world. After him followed Omar, who had been one of Mohammed's most faithful adherents, and then Othman and Ali, both sons-in-law of Mohammed. These four rulers are sometimes known as the "Orthodox" caliphs, because their right to the succession was universally acknowledged by Moslems. OMMIAD CALIPHS AT DAMASCUS, 661-750 A.D.