Mantou and Barbarians
According to Professor De Bao Xu, momo (馍馍) came from mantou (饅頭). Mantou is a soft and fluffy Chinese steamed bread typically eaten as a staple in northern parts of China where wheat is grown in abundant. They are made with milled wheat flour, water and leavening agents. White mantou were considered luxury in preindustrial China since the white flour used was heavily processed.
Mantou is made of three radicals, 食, 曼 and 頭, in which the first radical, 食 has an interesting story of its own. Zhuge Liang, the chancellor of Shu Han dynasty, led his army in an invasion of southern China (modern day Yunnan and northern Burma). After his victory over the barbarian King Meng Huo, Liang was leading the army back to Shu when a swift-flowing river blocked him and his army. Only sacrificing 50 men and their heads into the river would appease the river’s spirit and would allow them to cross. Liang, instead, killed the cows and horses his army brought along, and filled their meat into buns shaped roughly like human heads - round with a flat base - to be made and then threw them into the river. Hence, they tricked the river into thinking that the human heads were stuffed inside although it really was not, and thus successfully crossed the river. Those buns "barbarian's head" or mántóu then evolved into the present day mantou.
Although in Shu Han dynasty, mantou meant both filled and unfilled buns, it was identified as only filled buns later in Song dynasty (ca. 960 BC – 1279 BC). However, in some regions such as Jiangnan, it is stilled identified as both filled and unfilled buns. Likewise, in some other regions of China such as the province of Shanxi, mantou (饅頭) is called momo (饃饃) based on its characteristic of "steamed bun". Momo then made its entry into Tibet as momo (མོག་མོག) via various cultural exchanges that took place between China and Tibet.