Because after crossing over, I wasn't able to retain the original host's memories... though even if I had, they might not have been of much use.
Wang Yunxiao knew nothing about the historical background of this world.
This wasn't a gap that could be filled by glancing through a history textbook a couple of times.
Who hasn't gone through nine years of compulsory education in later generations, where any so-called expert can appear on TV to spin a tale, and still many people would believe them without a doubt?
History textbooks actually aren't that interesting, the only difference being that the Han Chinese dynasties have continued to this day, with no records of foreign tribes ruling the Central Plains.
The truly earth-shaking changes happened in recent decades, none of which is reflected in the textbooks.