Can’t speak for all Chinese dynasties; there have been a ton of them. But in recent(ish) history, the Yuan Dynasty was founded by the Mongols, a culture which at the time didn’t use family names (clans had names, but they weren’t conventionally linked with personal names), and spun up their dynastic name more or less out of whole cloth; the family name of the Ming emperors was Zhū; and the Qing emperors came from the Manchurian Aisin-Gioro family.
From what I’ve read, the founders of each dynasty gave it its name as, essentially, a propaganda move.
The family name of whoever came out on top of the squabble each time the civilization collapsed.
Can’t speak for all Chinese dynasties; there have been a ton of them. But in recent(ish) history, the Yuan Dynasty was founded by the Mongols, a culture which at the time didn’t use family names (clans had names, but they weren’t conventionally linked with personal names), and spun up their dynastic name more or less out of whole cloth; the family name of the Ming emperors was Zhū; and the Qing emperors came from the Manchurian Aisin-Gioro family.
From what I’ve read, the founders of each dynasty gave it its name as, essentially, a propaganda move.