Meanwhile, the spirit of Christian Spain, though broken, was not crushed. Its stronghold was at first the little kingdom of Asturias. Alfonso I not only resisted conquest but wrested back from the Moor the provinces of Galicia and Cantabria. From the northwest fastnesses of the Peninsula commenced the steady pressure southward, which, while it met with many reverses, was never abandoned until the invader had been driven back to Africa. The story in brief is one of gradual consolidation of the Christian power, accompanied by a corresponding disintegration of the Moslem. Léon becomes united with the other provinces and Castile follows suit; while on the other hand the Caliphate of Cordova becomes broken up into several dynasties. Then, while a rival sect, the Almoravides, arrive from Africa and make war on their co-religionists, Alfonso IV of Castile assumes the title of Emperor and captures Toledo and Valencia. Later, the conquests of the Almoravides are wrested from them by other arrivals from Africa, the fanatical sect of the Almohades. Encouraged by this dissension, the Christian states for the first time send their representatives to a national assembly. The first Cortes meets at Burgos. Six years later the Christians suffer defeat, but recover themselves and inflict a heavy blow upon the Moors at the battle of Las Navas de Tolosa. It is followed by repeated hammering, extending over nearly forty years, until the Moorish power is beaten back and by the year 1251 is confined entirely to the kingdom of Granada.