I'm reading The Palestine-Israel Conflict: A Basic Introduction by Gregory Harms and Todd M. Ferry, and it says this:
After Genghis’s death in 1227, one of his grandsons, Hulegu, decided to move the conquest further west with the intent of driving his forces all the way through the Middle East as far as Egypt. In 1256 Hulegu ploughed through the territories of Iran, Iraq, and Syria. By 1258 the Mongols had reached Baghdad and laid waste to libraries, mosques, and centuries worth of physical history. Estimates vary, but it’s safe to say that a million people were slaughtered during the siege (though Christians and Jews were spared).
Is this the case, as far as we can tell? If so, why did Hulegu choose to spare Jews/Christians?
Listening to Dan Carlin's audio over Ghengis Khan he covers this. He details how that Nestorian Christianity was common amongst the many wives of the khans, hulagu's wife is no different. This and the first contact with the Pope at this time would have an impact on some of the targets. Although it's essential to point out geographically the mongols targeted today's Middle Eastern city's like Baghdad before they campaigned further. There was another of Genghis Khans grandsons who followed the Islamic traditions, and when the khan dies, this leads to the decline of the apex of the great Mongolian empire, 1260.