The Soyombo script was developed by the Mongolian monk and scholar Bogdo Zanabazar in 1686 to write Mongolian. According to legend, Zanabazar based the script on letter-like signs he saw in the sky one night. Other theories suggest that the shapes of the letters may have been based on the Ranjana script of Nepal.
The Mongolian language had been written for centuries before the creation of Soyombo, using the Mongolian script, but Zanabazar was the first to write it horizontally.
Soyombo can also be used to write Tibetan and Sanskrit.