Mongolia had no written language. When Genghis Khan attacked Naiman in 1204 AD, he captured Tata Tong, the official who was the seal of Naiman. Tata Tong was a man of fear and was proficient in fear and language. Following Temuzhen's wishes, he wrote Mongolian characters in fear and children to educate Temuzhen's nephews, and created the Mongolian language of fear and children, or the Mongolian language of the Uighur body. Kublai Khan believed that the Mongolian language of fear and children was just a borrowing of words and could not be counted as Mongolia's own writing, so Kublai Khan decided to create a new type of writing for the unified use of the whole country soon after he succeeded the Khan in the Yuan Dynasty (now the site of the Zhenglan Banner of the Ximeng). In the first year of the Central Dynasty (AD 1260), the famous Tubo lama Ba Siba was appointed to create it.

Ba Siba spelled the Mongolian language in the Uyghur alphabet as the Mongolian script, which played a certain role in the improvement of Mongolian culture and the implementation of national decrees. Yuan Dynasty Patriarch Kublai Khan ordered the national teacher Ba Siba to create a new Mongolian character, and Fang Ba Siba led a group of language scholars to re-make it according to the Tibetan alphabet, imitating the square shape of Chinese characters, spelling it from top to bottom, called the Mongolian new character. Mongolia promulgated the world on February 13, the sixth year of the new year, and used it as an official character. Also known as "Ba Siba character".

Ba Siba (1235~ 1280), his real name was Luo Zhuijianzan. Tibetan politician and Buddhist master, the fifth-generation patriarch of the Sakya school of Tibetan Buddhism, and the first emperor of the Yuan Dynasty. Ba Siba was born into a well-known family. He was intelligent and knowledgeable since childhood, and was well versed in Buddhism. He was known as a holy child. It is said that he could recite lotus practice when he was 3 years old, recite 100,000-word Buddhist sutras when he was 7 years old, and recite scriptures when he was 8 years old. At the age of 9, he lectured others at puja meetings, so he was called "Ba Siba" (meaning "saint" and "child prodigy"). In the fourth year of Chunyou in the Southern Song Dynasty (1244 AD), Ba Siba and his brother Chana Dorjee went to Liangzhou (now Wuwei, Gansu Province) with his uncle Saban to meet Kuduan, In the 11th year of Chunyou (1251 AD), he was summoned to Liupan Mountain to meet Kublai Khan. Ba Siba won Kublai Khan's appreciation for his profound knowledge and modest and prudent virtue. He was highly revered and was revered as a "guru". In the same year, Saban died of illness, and Ba Siba continued to be the new king of the Sakya sect. Since the first year of Baoyou (1253 AD), Kublai Khan, his princess and children were all empowered by Tantra and converted to Tibetan Buddhism.

Baspawen seal

In the first year of Yuan Zhongtong (1260 AD), Ba Siba was appointed as the imperial teacher, "awarded the jade seal", and served as the head of the Zhongyuan Dharma to manage the Buddhist affairs of the country. At the same time, according to the road conditions, post stations were set up to ensure the smooth flow of the road, which laid a solid foundation for the effective control and administration of the central government of the Yuan Dynasty over the Xizang area, and also communicated the economic and cultural exchanges between Xizang and the mainland of the motherland.

In the first year of the Yuan Dynasty (1264 AD), Ba Siba, as the national teacher and head of the hospital, managed the affairs of Buddhism and Tibetan areas across the country, and became a senior Tibetan official of the central government. After two years, he returned to Tibet to establish local administrative institutions in Tibetan areas for the Yuan Dynasty. Established the famous political and religious regime in Tibetan history, the Sakya local regime. The regime effectively exercised the management of Xizang local political and religious affairs on behalf of the central government of the Yuan Dynasty. In the sixth year of the Yuan Dynasty (1269 AD), he returned to Dadu (now Beijing) and created a new Mongolian character, "Ba Siba Character", which was promulgated throughout the country. The following year, he was promoted to "Emperor", was named "Dabao Dharma King", and was given a jade seal. He commanded 130,000 households in Xizang.