[quote=Leos Klien]
That's the old empire Cale. I could be wrong. But I think it underwent reformation during those eras. This is, at least 400 years ahead of the events that took place in Morowind. 
[/quote]

200 years actually. If my TES lore is correct, an era ends whenever something significant happens instead of it based on a period of time. For example, 1E lasted for 13 centuries while the 3E only lasted for five centuries. The Skyrim Civil War and the Return of the World-Eater takes place in the 201st year of the 4th Era so yeah, 200 or so years.