The Mongols were savages. I've covered this topic not too long ago on the other board
Sir Thomas Arnold wrote in "Muslim civilization during the Abbias Period:
"Muslim civilisation has never recovered from the destructions which the Mongols inflicted upon it. Great centres of culture, such as Herat and Bukhara, were reduced to ashes and the Muslim population was ruthlessly massacred..... Under the command of Hulagu, they appeared before the walls of Baghdad, and after a brief siege of one month the last Caliph of the Abbasid house, Mustasim, had to surrender, was put to death togheter with most of the members of his family; 800,000 of the inhabitants were brought out in batches from the city to be massacred, and the greater part of the city itself was destroyed by fire.
Glubb's concludes in one of his books:
"For five hundred years, Baghdad had been a city of palaces, mosques, libraries and colleges. Its universities and hospitals were the most up to date in the world. Nothing now remained but heaps of rubble and a stench of decaying human flesh."
Syria also suffered a similiar fate. For example, in Aleppo, at the time of the Frankish invasion, the country's population stood at 2.7 million inhabitants. Two centures later (1342), after the invasion of the Mongols, it only stood at 1.2 millions.
The famous British historian Gibbon narrates:
"Timur's front was covered with a line of Indian elephants, whose turrets were filled with archers and Greek fire: the rapid evolutions of his cavalry completed the dismay and disorder; the Syruans fell back on each other: many thousands were stifled or slaughtered in the entrance of the great street; the Moguls entered with the fugitives; and after a short defence, the citadel, the impregnable citadel of Aleppo, was surrendered. Among the supplicants and captives, Timur distinguished the doctors of the law, whom he invited to the dangerous honour of a personal conference... During this peaceful conversation, the streets of Aleppo streamed with blood, and re-echoed with the cries of mothers and children, with the shrieks of violated virgins. The rich plunder that was abandoned to his soldiers might stimulate their avarice; but their cruelty was enforced by the peremptory command of producing an adequate number of heads, which, according to his custom, were curiously piled in columns and pyramids; the Moguls celebrated the feast of victory, while the surviving Muslims passed the night in tears and in chains. I shall not dwell on the march of the destroyer from Aleppo to Damascus, where he was rudely encountered, and almost overthrown, by the armies of Egypt. ...I shall briefly mention that he erected on the ruins of Baghdad a pyrmid of ninety thousand heads"