Once they had captured Nishapur, Mu'izz al-Din was sent on an expedition towards Ray, but he let his troops get out of control and got little further than Gurgan, earning criticism from Ghiyath which led to the only reported quarrel between the brothers.

Ghiyath, not glad about Tajuddin controlling Ghazni, and not daring to leave Ghur unprotected, requested help from the Muhammad II.

Muhammad II then captured Samarkand in 1207 from the Kara Khitay, Tabaristan in 1210 from Bavandids and Transoxiana from Western Karakhanids.

He pursued expansionist policy and conquered Tashkent and Fergana from Western Karakhanids and regions of Makran and Balochistan from Ghurids and Atabegs of Azerbaijan become his vassals in 1211.

Having only recently conquered two-thirds of the Jin dynasty and capturing Beijing, Genghis was looking to open trade relations, but having heard exaggerated reports of the Mongols, the Shah believed this gesture was only a ploy to invade his land.

[10] Trying to maintain diplomacy, Genghis sent an envoy of three men to the Shah, to give him a chance to disclaim all knowledge of the governor's actions and hand him over to the Mongols for punishment.

[11] These events led Genghis to retaliate with a force of 100,000 to 150,000 men that crossed the Jaxartes in 1219 and sacked the cities of Samarkand, Bukhara, Otrar and others.

Ala ad-Din Muhammad fled and sought refuge in Khorasan,[citation needed] and later died of pleurisy on an island in the Caspian Sea near the port of Abaskun some weeks later.