What script was adapted for writing Mongolian under Genghis Khan?

Under Genghis Khan, the Uyghur script was adapted to write the Mongolian language. The adoption occurred around 1204, before the formal establishment of the Mongol Empire, after Genghis Khan defeated the Naiman and brought the Uyghur scribe Tata-tonga into his service.

The Mongols were highly effective oral communicators, but governing a growing empire required written records for taxation, diplomacy, military orders, and administration. The Uyghur writing tradition provided a practical model. The adapted script became the traditional Mongolian script, written vertically in columns that run from left to right.

The script was not simply a new alphabet invented from scratch. It ultimately descended through Uyghur and Sogdian forms from the Aramaic writing tradition. Mongolian scribes modified it to represent the sounds and grammatical needs of Mongolian. Its use helped preserve official documents, legal texts, Buddhist works, and historical writing across the Mongol world.

Cyrillic is a much later development. Mongolia adopted a modified Cyrillic alphabet in the 20th century, especially after the 1940s, while the traditional script remains in active use in Inner Mongolia and has been revived alongside Cyrillic in modern Mongolia. Chinese and Arabic scripts were used in some local contexts, but neither was the script adopted under Genghis Khan.