What was the mongol empires writing system?

Many alphabets have been devised for the Mongolian language over the centuries, and from a variety of scripts. The oldest, called simply the Mongolian script, has been the predominant script during most of Mongolian history, and is still in active use today in the Inner Mongolia region of China and de facto use in Mongolia. It has spawned several alphabets, either as attempts to fix its perceived shortcomings, or to allow the notation of other languages, such as Sanskrit and Tibetan. In the 20th century, Mongolia first switched to the Latin script, and then almost immediately replaced it with the Cyrillic script for compatibility with the Soviet Union, its political ally of the time. Mongol Chinese in Inner Mongolia and other parts of China, on the other hand, continue to use alphabets based on the traditional Mongolian script.