[hospes]

>> If it is regional, it is not an empire...

Armenia was an Empire long before Ani. List of Largest Empires in Wikipedia: https://en.wikipedia.org/wiki/List_of_largest_empires If you look at "Ancient Empires" section, there are only 6 empires and both Armenia and China are in the list.

>> China was an empire, and was forgotten.

I do not think that is the case. I have never seen any respectable historical atlas that does not have China. Also there are Hollywood movies depicting China in times when it was (or was becoming) an Empire, so you can hardly call it forgotten.

The main reason that Chinese Empire is not forgotten and won't be anytime soon, is that China is still a major power with 1.357 billion population.