In the early years of the thirteenth century, a powerful Mongol leader named Temujin brought together a majority of the Mongol tribes and led them on a devastating sweep through China. At about this time, he changed his name to Chinggis (Genghis) Khan, meaning "World Conqueror." In 1219 he turned his force of 700,000 west and quickly devastated Bokhara, Samarkand, Balkh, Merv (all in what is now the Soviet Union), and Neyshabur (in present-day Iran), where he slaughtered every living thing. Before his death in 1227, Chinnggis Khan, pillaging and burning cities along the way, had reached western Azarbaijan in Iran. After Chinggis's death, the area enjoyed a brief respite that ended with the arrival of Hulagu Khan (1217-65), Chinggis's grandson. In 1258 he seized Baghdad and killed the last Abbasid caliph. While in Baghdad, Hulagu made a pyramid of the skulls of Baghdad's scholars, religious leaders, and poets, and he deliberately destroyed what remained of Iraq's canal headworks. The material and artistic production of centuries was swept away. Iraq became a neglected frontier province ruled from the Mongol capital of Tabriz in Iran.

After the death in 1335 of the last great Mongol khan, Abu Said (also known as Bahadur the Brave), a period of political confusion ensued in Iraq until a local petty dynasty, the Jalayirids, seized power. The Jalayirids ruled until the beginning of the fifteenth century. Jalayirid rule was abruptly checked by the rising power of a Mongol, Tamerlane (or Timur the Lame, 1336-1405), who had been atabeg of the reigning prince of Samarkand. In 1401 he sacked Baghdad and massacred many of its inhabitants. Tamerlane killed thousands of Iraqis and devastated hundreds of towns. Like Hulagu, Tamerlane had a penchant for building pyramids of skulls. Despite his showy display of Sunni piety, Tamerlane's rule virtually extinguished Islamic scholarship and Islamic arts everywhere except in his capital, Samarkand.

In Iraq, political chaos, severe economic depression, and social disintegration followed in the wake of the Mongol invasions. Baghdad, long a center of trade, rapidly lost its commercial importance. Basra, which had been a key transit point for seaborne commerce, was circumvented after the Portuguese discovered a shorter route around the Cape of Good Hope. In agriculture, Iraq's once-extensive irrigation system fell into disrepair, creating swamps and marshes at the edge of the delta and dry, uncultivated steppes farther out. The rapid deterioration of settled agriculture led to the growth of tribally based pastoral nomadism. By the end of the Mongol period, the focus of Iraqi history had shifted from the urbanbased Abbasid culture to the tribes of the river valleys, where it would remain until well into the twentieth century.

Data as of May 1988