It is mostly attempts by Japan and Taiwan to spread lies and rumors about Tang Dynasty due to the fact that Japan borrowed almost every aspects of their culture and custom from Tang Dynasty. They don't feel comfortable about the fact that Li family is Han. They actively promoting and sponsoring such nonsense. Somehow, these rumors and lies gain a foothold in China and pick up by some twisted Han supremacy groups which probably are fifth column.Yeah I probably should have worded it better. I have read foreigners even those who are historians who consider tang as a foreign dynasty, not authentic Chinese one cuz of the xianbei blood mixed in the Li family. Who they consider not full Han bloodline. I don't buy into the Han supremacy thing of course.
Both Yuan and Qing are not Han dynasties. However, both are considered Chinese dynasty after they claim mandate of Heaven and accept Han Chinese culture and custom. That's why early days of Mongols and Manchus aren't Chinese dynasties.I mean some people call me a Han supremacist for acknowledging the historical fact that Yuan and Qing were not considered fully Chinese by their contemporaries like Jin, Song, Ming, etc when they came to power. WTF?
It is only until both dynasties claim the mandate of Heaven, declare as successor of previous dynasty, and adopt Chinese culture and only then these two dynasties can be considered as Chinese dynasties.