These campaigns led to the termination of the Khwarazmian Empire, the Nizari Ismaili state, and the Abbasid Caliphate of Baghdad, and the establishment of the Mongol Ilkhanate government in their place in Persia.

After a series of diplomatic provocations on the part of Muhammad II, the ruler of the neighbouring Khwarazmian Empire, the Mongols launched an invasion in 1219.

Soon after his accession to the khaganate in 1227, Ögedei Khan sent an army under Chormaqan Noyan to end Jalal al-Din's renewed resistance and subjugate several minor polities in Persia.

On the orders of his brother, Möngke Khan, Hulagu systematically captured the fortresses of the Nizari Ismaili state in northern Persia, seizing their capital of Alamut in 1256.

In order to destroy the Khwarazmian Empire, Al-Nasir not only provoked the Ghurids and fanatical religious scholars from Transoxiana against it, but also asked help from the Nizari Ismaili state, the Qara Khitai and Mongol tribes.

In the 12th century, a group of Khitan people from North China who were Buddhists, had formed a large political entity in the province of Kashgar and Hotan called Qara Khitai.

Kuchlug defeated them in Transoxiana and conquered Bukhara and Samarkand, usurping the Qara Khitai Empire from his father-in-law Yelü Zhilugu.

As a Mongol detachment led by Jebe hunted Kuchlug down, he fled; meanwhile, Muhammad was able to vassalize the territories of Balochistan and Makran in modern-day Pakistan and Iran, and to gain the allegiance of the Eldiguzids.

[5] After extending the borders of the Khwarazmian Empire from the north-east and east to Kashgar and the Sindh, Shah Muhammad decided to conquer the west, i.e. Iraq.

As a result of this dispute and enmity, Shah Muhammad received a fatwa from the scholars of his country that "Bani Abbas" do not deserve the caliphate and one of "Husayni Sadat" (a person from the generation of Imam Husayn) should be chosen for this position.

In 1217, Shah Muhammad marched towards Baghdad, but because it was winter, his troops suffered a lot from the snow and cold in the Asadabad pass between Kermanshah and Hamadan, and thus he returned to Khorasan.

So, he sent a group of his merchants headed by Mahmud Yalavach with gifts to visit Shah Muhammad and inform him about the size of his country, prosperity of his possessions, and the strength of his army.

[6] In this way, the first ambassador of Shah Muhammad was accepted in Beijing, and Genghis declared trade between the Mongols and Khwarazmians as a necessity for establishing friendly relations.

During this situation, a number of Muslim merchants from Shah Muhammad's territory took some goods to the Mongol Empire, and although Genghis treated them violently at the beginning of their arrival, he finally appeased them and sent them back with respect.

[8]: 701 [9] When the news of Otrar incident reached Genghis Khan, he decided to control his anger and made his last attempt to gain satisfaction through diplomacy.

But the conflict between Shah Muhammad and Kuchlug Khan, the leader of the Naimans, had caused the closure of the roads and the interruption between the east and west trade.

Imam Shahab al-Din Khiyoqi, one of the famous jurists and teachers of Khwarazm, proposed to bring as many soldiers as possible from different corners of the empire and prevent Mongols from crossing Syr Darya (medieval Arabs called this river Seyhan) but the commanders of the Khwarazmian army did not fancy his plan.

The Shah didn't give importance to the counsel of Shahab al-Din, and accepted the plan of scattering his troops to protect major cities of the empire.

The Khan's march through the Kyzylkum Desert had left the Shah's field army impotent, unable to either engage the enemy or help his people.