As Bagdad, from the circumstance of no khalif having died within its walls, merited, most peculiarly, the name of the House, Valley, or City of Peace; so, also, on account of the great number of holy men of Islam, who are buried within or without it, and whose tombs are so many objects of the pilgrimages of the Moslimin, it gained the title of Bulwark of the Holy. Here are the mausolea of the greatest imams and the most pious sheikhs. Here reposes the Imam Mussa Kasim, the seventh of the twelve imams, who, in direct descent from Ali, claimed the right to the throne and the khalifat, on account of their relationship to the prophet; also, the imams, Hanefi and Hanbeli, the founders of two of the four orthodox sects of the Sunna; the sheikhs, Juneid, Shobli, and Abdolkadir-Ghilani,[268] the chiefs of the mystic sect of the sofis. In the midst of the monuments of the imams and sheikhs, stand those of the khalifs, and their spouses; of which that of Zobeide, the wife of Harun al Rashid, has, by the strength of its construction, survived the repeated captures and destructions of Bagdad, by the Mongols, Persians, and Turks. Equally splendid specimens of Saracenic architecture are the academies, colleges, and schools; two of which have immortalized the names of their founders in the history of Arabic literature. The academies, Nisamie and Mostansarie, the former instituted in the first half of the fifth century of the Hegira, by Nisam-ol-mulk, the great grand-vizier of Melekshah, sultan of the Seljuks, the latter, built two centuries later, by the Khalif Almostansar-billah, with four different pulpits for the four orthodox sects of the Sunnites.