佛祖統紀 48.42

48.42

四年。詔以新製蒙古字頒行天下。初上命帝師八合思八製蒙古新字。其字僅千餘。其母凡四十有一。其相關紐而成字者。則有韻關之法。其以二合三合四合而成字者。則有語韻之法。而大要則以諧聲為也。至是詔頒行之。

In the fourth year, an imperial decree promulgated the newly created Mongolian script throughout the realm. Earlier, the emperor had commanded Imperial Preceptor 'Phags-pa to create a new Mongolian script. Its characters numbered only a little over a thousand, with forty-one letters. For those that were combined and linked to form characters, there were the rules of rhyme articulation; for those formed by combining two, three, or four sounds, there were the rules of phonetic rhyme; and the essential principle was to rely on harmonious sounds. At this point, an imperial decree promulgated it.