How did the modern Chinese historians create a national history? One aspect of this is the creation of protohistory, explaining what was going on in a place before there was much of a recorded history. This was a big problem in Europe in the 19th century. Having cut loose from the biblical narrative there were a lot of years to fill up, very little archaeological evidence, some vague references in classical works and a host of stories about ancient heroes. (Did you know that Adam was actually buried in England? I think Aeneas visited too.) A lot of work went into creating a reasonably accurate narrative of European protohistory, much of it built around successive waves of invaders.
Chinese historians took to this problem surprisingly well. Before the Qing there was not much on the origins of China, as distinct from the origins of civilization, although they did have a longer timeline and plenty of stories to fit in there. Liu Shipei and Zhang Binglin were both believers in the “Western origins” theory which held that the Chinese had originally been called the Baks and came from Mesopotamia. They roamed around Central Asia for a while then, under the leadership of Huangdi, they moved into the Yellow River valley, displaced the Miao and started calling themselves Han.
I get this from Peter Zarrow1 who says that it was a popular theory in the late Qing, especially with anti-Manchu revolutionaries (trying to draw a more clear divide between the Manchus and the Han?) but he does not know much about it.2 It strikes me as possibly having been influenced by missionary writings, given that 19th century people seem (to my limited knowledge) very wrapped up in tying their protohistory to the Bible and the Middle East (The first Irish person, for instance, was Cessair, the granddaughter of Noah). It certainly does not seem to have had much influence in the present, when popular understanding of Chinese history is pretty anti-diffusionist.
*and the rise of the sons of Aryas, obviously