I'm a bit disappointed about the complete lack of even mentioning the Argonian Takeover of Morrowind, and the obliteration of Vvardenfell isn't really mentioned that much. The An-Xileel are the equivalent to the Thalmor, in terms of ruling political parties. In reality, there are 3 empires. It seems like it is completely ignored, which is a bit disappointing. The empire is only cyrodiil, half of skyrim, and highrock as of 4E201.

Here's a map for ya:

http://elderscrolls.wikia.com/index.php?title=Tamriel&image=Tamriel_4E-png

There is a quest Journal in the game that talks about the Argonian takeover.

Location:

the argonians left Morrowind after they "took over"
It was more like a raid