The Mongolian’s had an unusual religious tolerance for the time. Genghis Khan himself only ever worshipped the ‘Eternal Blue Sky’ who was his God; the Golden Light of the Sun; and the vast array of spirits in the nature around them. He believed that God was physically represented by the earth – the rivers carrying the soul. Khan was a very religious man, and before going to war would always seek the permission of the Eternal Blue Sky, believing any military success to be because God deemed that his enemies should be punished.

Although Khan remained loyal only to the Eternal Blue Sky, he was exposed to a large variety of religions from the beginning of his military career. Many of the other tribes in the Steppes that are now part of Modern Mongolia had been converted to Christianity, Buddhism or Islam by the 13th century. For example, the Assyrian Church had sent missionaries west several centuries earlier – Christianity became popular due to awe of Jesus’ healing powers and life after death. It was in his early attempts to conquer the other tribes of the Steppes where Genghis first showed his willingness to overlook religion in favour of loyalty between friends.

After nearly falling into a trap set by Ong Khan, the leader of a Steppe tribe, Genghis and some of his most loyal followers fled to the waters of Baljuna. They numbered at just 19, and it is only known that Genghis and his brother Khasar were from Mongolian clans. The others were many Buddhists, Muslims and Christians. Next to the water, a divine sign in the form of a horse appeared – recognised by all present as the holiest animal. This led to all the 19 swearing eternal loyalty to Genghis – an oath that supersedes religion, kinship, and ethnicity. Known as the Baljuna covenant, knowledge of the event was passed down through oral tradition and is used as a metaphor for how religion would be treated in the Mongol Empire.

Now we can move forward to Genghis’ attempt to unite all the clans of the Steppes (modern Mongolia). For decades, the clans of the Steppes had warred over religion, with religion being the decisive factor in the clans’ borders. Having won a military victory over all the clans in the Steppes, Genghis now attempted to bind them into one nation. He created – and continued to work upon for the rest of his life – the Great Law. This outlawed the kidnapping of women, outlined rules for hunting animals, and most importantly granted total religious freedom for everyone. Genghis both needed feuds within the Steppe clans and tribes to end and for loyalty from all members of his new nation, and he viewed religious freedom as a necessary step in achieving that. By now, there were representations of most religions somewhere on the Steppe, and Genghis believed that ultimately, they all aimed towards the same God – that of the Eternal Blue Sky – even if they didn’t quite get it right.

It must be understood that this is from where the Mongolian army was formed. A vast pool of multiculturalism, ethnicities and religions. The riders in the army could have been side by side with a Christian, a Muslim and a Buddhist as they rode towards Christian Georgia, or Daoist China.

So, each soldiers perception of a religion was different but one of the keys of Mongolian success was religion took lesser importance than loyalty. Regardless of religion, Mongolian soldiers believed that when they were attacking a city, they were there to bestow the punishment of God on its leaders. For the most part, religious leaders of an invaded territory were safe. While other leaders and the aristocracy of an invaded city would be executed (mostly) Khan would place many clerics and scholars under his protection, freeing them from danger. Although Khan himself only vary rarely would enter a captured city, his loyal followers would carry always keep the orders of religious freedom in mind when looting and pillaging.

Even more rarely than entering a city for Khan was to enter a religious building. Khan’s personal thoughts about other religions are little known, but Historians understand that Genghis found the idea of trapping a god within a building like a Mosque or Church to be offensive, as the Eternal Blue Sky should roam free over all of the earth. He also believed that God’s words could not be confined to writings or a book and that if God was to speak to a person, he could do so directly, as he believed God had done so to himself many times. Despite this, his belief that religions mostly had the right idea meant that he never looked to persecute anyone for their religious beliefs.

To summarise, religion within the Mongol army was extremely diverse and tolerant. They did not greatly care for the religion of the place they were invading – only the goods that could be looted and that God had willed for the invasion. While Genghis Khan himself didn’t believe that any religion other than that of his Eternal Blue Sky existed, he recognised the benefits of religious freedom and used them to his advantage in creating his empire. His army represented the belief, and although there may have been strife between different religions within the empire – they all had to obey the Great Law and provide total religious freedom.

I realise I may not have directly answered the question, but that is because the question is somewhat based on a misunderstanding. Christianity and Islam were part of the Mongol Empire and the Mongolian’s were a part of Christianity and Islam, so there isn’t a direct ‘what is this new religion’ moment when the Mongols invade.

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Weatherford, J. (2005). Genghis Khan and the Making of the Modern World.

Rossabi, M. (2012). The Mongols: A Very Short Introduction.

May, T. (2018). The Mongol Empire.

Man, J. (2014). The Mongol Empire: Genghis Khan, his heirs and the founding of modern China.