Jumping through the records, this already explains a lot. Even if the information controlled by the Dou Family isn't entirely accurate, it at least proves they conducted investigations before compiling the genealogy, and a fairly comprehensive one at that. If it was just for name-dropping, Wan Ping's formerly somewhat famous second brother wouldn't be singled out and not written about.
However, the Wan Family has lived in the Moon Corner Duchy for a very long time, even residing here before the Moon Corner Duchy was fully formed. They consider themselves citizens of the Moon Corner Duchy externally. The name "Wang" changed to one of a relatively historical family surname in the Moon Corner Duchy, and the Wan Family's ability to occupy land and live in the border town is due to their strong connections.
