historians believe that the Mongol invasion destroyed much of the irrigation infrastructure that had sustained Mesopotamia for millennia. Other historians point to soil salination as the culprit in the decline in agriculture.
The mid-14th-century Black Death ravaged much of the Islamic world. The best estimate for the Middle East is a death rate of a third.
In 1401, warlord of Mongol descent Tamerlane (Timur Lenk) invaded Iraq. After the capture of Baghdad, 20,000 of its citizens were massacred. Timur ordered that every soldier should return with at least two severed human heads to show him (many warriors were so scared they killed prisoners captured earlier in the campaign just to ensure they had heads to present to Timur).
Ottoman Empire
During the late 14th and early 15th centuries, the Black Sheep Turkmen ruled the area now known as Iraq. In 1466, the White Sheep Turkmen defeated the Black Sheep and took control. In the 16th century, most of the territory of present-day Iraq came under the control of Ottoman Empire as the pashalik of Baghdad. Throughout most of the period of Ottoman rule (1533–1918) the territory of present-day Iraq was a battle zone between the rival regional empires and tribal alliances. The Safavid dynasty of Iran briefly asserted their hegemony over Iraq in the periods of 1508–1533 and 1622–1638.
By the 17th century, the frequent conflicts with the Safavids had sapped the strength of the Ottoman Empire and had weakened its control over its provinces. The nomadic population swelled with the influx of bedouins from Najd, in the Arabian Peninsula. Bedouin raids on settled areas became impossible to curb.
During the years 1747–1831 Iraq was ruled by the Mamluk officers of Circassian origin who succeeded in obtaining autonomy from the Ottoman Porte, suppressed tribal revolts, curbed the power of the Janissaries, restored order and introduced a program of modernization of economy and
