The Mongol Il-Khans (1258-1335)
At the time of an-Nasir's death in 1225, the Mongols under Genghis Khan (d. 1227) had already destroyed the state of the Khwarezm-Shahs and conquered much of northern Iran. The armies of the 'Abbasid caliph al-Mustansir (1226-42), an-Nasir's grandson, managed to drive off a Mongol attack on Arabian Iraq.Under his son, al-Musta'sim (1242-58), the Mongols laid siege to Baghdad in 1245 without success. A series of terrible floods in 1243, 1253, 1255, and 1256 undermined the defenses of the city, the prosperity of the region, and the confidence of the populace.
In 1258 Baghdad was invested by a major Mongol force commanded by the non-Muslim Hülegü, a grandson of Genghis Khan, who had been sent from Mongolia expressly to deal with the 'Abbasids. The city fell on Feb. 10, 1258, and al-Musta'sim was executed shortly thereafter. Although the Mamluk sultans of Egypt and Syria later raised a figurehead or "shadow" caliph in Cairo, and after the Ottoman conquest of Egypt in 1517 the Ottoman sultans used the title caliph until the Ottoman "caliphate" was abolished by Mustafa Kemal (Atatürk) in 1924, the death of al-Musta'sim--the last universally recognized caliph--in fact represents the end of this great Islamic religio-political institution.
Physically much of Baghdad was destroyed, and it is said that 800,000 of its inhabitants perished. Administratively the city was relegated to the status of a provincial centre. Other cities in Arabian Iraq, such as Al-Hillah, Al-Kufah, and Basra, readily came to terms with the conqueror and were spared. In Upper Iraq, Mosul was made the capital of the provinces of Diyar Bakr and Diyar Rabi'a. These provinces, like Arabian Iraq, were dependencies of the new Il-Khan Mongol polity, which was based in Azerbaijan. (The Il-Khans in turn were nominally subordinate to the Great Khan in China.)
Although Baghdad may have retained a certain symbolic aura for Muslims, the city of Tabriz in Azerbaijan rapidly replaced it as the major commercial and political hub of the region. Mongol rule in Baghdad and Mosul generally took the form of a condominium consisting of a Muslim, Christian, or Jewish civilian administrator seconded by a Mongol garrison commander.
Although under the Muslim Juvayni family of Khorasan (1258-85) there is some evidence that Baghdad began to recover somewhat from the devastation it had suffered at the hands of the Mongols, in general Iraq experienced a period of severe political and economic decline that was to last well into the 16th century. Later on, despite the conversion to Islam of the Il-Khan Mahmud Ghazan (1295-1304) and the centralizing reforms of his minister Rashid ad-Din (d. 1318), according to one source, state or diwan revenues in Arabian Iraq fell from more than 30 million dinars in pre-Mongol times to 3 million in 1335-40.
