There are two buildings still extant in Spain which have survived the Arabs, viz., their mosque at Cordova (now the Cathedral), and their palace of the Alhambra at Granada, both well worth a visit, and well described in Murray's and O'Shea's guides to Spain. During the reign of Abd-ar-Rahman III. (A.D. 912-961) the city, palace, and gardens of Medinatu-z-Ahra, three or four miles from Cordova, were constructed in honour of his favourite wife or mistress, Az-zahra, and cost an immense sum of money. At present no vestiges of them exist, and it is supposed that not only these, but many other Arab mosques and buildings, were intentionally destroyed by their conquerors, as the hatred between the Christian and the Muslim in those days was of the bitterest description. And now to return to the Abbasides, established in the East on the downfall of the Omaiyide dynasty there in A.D. 750, and thus continue the main line of Arab history. There were, in all, thirty-seven Abbaside Khalifs, of whom Abu Jaafar, surnamed Al-Mansur, the Victorious (A.D. 754-775), Harun-ar-Rashid (A.D. 786-809), and Al-Mamun (A.D. 812-833) were the most celebrated. Of these, the first, who was the second Khalif, founded Baghdad, the capital of the Abbasides, about A.D. 762; the second, who was the fifth Khalif, has been rendered immortal by the frequent illusions to him, and to members of the Barmeki family, in the 'Arabian Nights'; while the third, who was the seventh Khalif, was a great patron of literature and science. As years rolled on the dynasty and its princes became weaker and weaker, and finally came to an end under the thirty-seventh and last Khalif Al-Mustaa 'sim Billah, with the capture of Baghdad in A.D. 1258 by Halaku Khan, the sovereign of the Mughals, and the grandson of Jenghiz Khan. Long before this, however, the empire which the first of the Abbasides had conquered was already broken up. About A.D. 879, in Persia, Amr-bin-Lais founded the Suffary or Braiser dynasty, still subject to the Commander of the Faithful. But even this allegiance only lasted till A.D. 901, when the Samani and Dailami dynasties were established in the North and South of Persia respectively, and quite independent of the Khalifs of Baghdad.