The beliefs of the Tatarian army started to change after their campaigns inEurope. Many of the Mongolian leaders married Christian girls, thereby giving an opportunity for Christianity to enter the Mongolian state relatively, which made cooperation between the Mongols and the Christians more possible.

After Guyug took office in 639 A.H. / 1241 A.D., he decided to stop all expansive campaigns, and instead devoted his efforts to establishing his power in the different parts of his kingdom. He ruled from 639 to 646 A.H. / 1241-1248 A.D., during which the Tatars added almost no territories to their dominion. It was a period of relative quietness in the regions neighboring the Tatars. But the regions which were stricken by the Tatars continued to suffer from the wrongness and viciousness of the Tatarian occupation.

In 640 A.H. / 1242 A.D., the Abbasid Caliph Al-Mustansir died and his son, Al- Musta‘sim, 30 years of age, became the Caliph. Despite the fact that he was known for reciting the Noble Quran and reading the Tafseer, he had no political awareness, and did not know how to choose his assistants. He took a corrupt retinue, and the caliphate became even weaker during his time. He was the last Abbasid Caliph, and during his time,Baghdadfell into the hands of the Tatars.

At the same time, King Louis IX, ofFrance, was preparing his armies to attackEgyptin what was known as the Seventh Crusade. In 646 A.H. / 1248 A.D. he started to mobilize his forces inCyprus. Not yet despairing of the possible alliance with the Tatars against the Muslims, he sent an embassy fromCyprustoMongoliaasking Guyug for support in this Crusade against the Muslims. The embassy had lots of precious gifts and valuable treasures for Guyug. But by the time they arrived toKarakorum, the Mongolian capital, Guyug had died and left only three young sons, unfit to rule. His widow, Oghul Qaimish, became their trustee, and thus ruled as a regent for three years, beginning from 646 A.H. / 1248 A.D.

Louis IX did his best to communicate with the Tatars, and ensure coordination with them for the attack against the Muslims, but Guyug’s widow apologized, due to her involvement in the internal conflicts over the throne. Louis IX insisted on carrying out his campaign, even without the Tatars, and headed toDamiettaand occupied it, but the Mamluk uprising towards the end of the Ayyubid era inEgyptwas able to defeat Louis IX and put an end to his campaign, and Louis IX himself was taken captive after the famous Mansoura Battle.

Meanwhile, inMongolia, the National Assembly of the Tatars, known as the Great Kurultai, held a meeting in 649 A.H. / 1251 A.D., and elected Mongke Khan as their new Khagan.

Electing Mongke Khan as the new Khagan of the Tatars was a radical turning point in their policy, and marked the beginning of a drastic change in the surrounding areas. He had an expansive policy similar to that of Genghis Khan who had established the kingdom of the Tatars, and also similar to that of Ogedei under whose ruleEuropewas conquered by the Tatars. Mongke Khan started to think about overthrowing the Abbasid Caliphate and the rest of the Muslim countries afterwards.

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