once and the rest can all be considered more of less as rebellions. After 1600 AD, the Manchurians conquered China and that is basically it. However fodder, I dont think emperors were beheaded ;P they were usually poisoned, assassinated, etc. One of the unique thing about China is.... emperor's were often puppets of their eunuch (technically)! Say... new class Eunuch would be cool ;p just kidding