Don't be jealous you were never one country like China.
Cantonese is a dialect, LOL, you don't even know the difference between dialect and language !?! There is only one chinese language. It's the world's oldest continuous language. And it's certainly not Persianized
The notion of one country is Sovereignty, it has nothing do with culture or religion. A country/empire may or may not share the same culture. Middle east share the same culture and religion, but they are not one country. Ancient Roman is one empire, but it is a mix mash of different culture and people. It is sovereignty that defines a country!! If you have 30 sovereign kings here and there, you are simply not one country/empire.