In the winter of A.D.1258, when the Mongols sacked Baghdad under Hulegu Khan, great destruction was visited upon the city and its inhabitants. The Bayt al Hikma, or House of Wisdom, was plundered ...
Studies of chroniclers and physicians from the time shows evidence of outbreaks in places including Syria, Iraq and Egypt in the years following the Mongol conquest of Baghdad in 1258.
In the middle of 13th century, the Mongol army already captured Kiev in 1240, took Alamut in 1256 and Baghdad in 1258, deposing and executing the last Abbasid Khalif Mustasim ‘ billah.