I did. The thalmor have all of it. The dominion consists of Valenwood and Summerset Isle. Elsweyr too.
No, you're missing quite a few key points. I'll help you.. http://elderscrolls.wikia.com/wiki/Second_Aldmeri_Dominion
"In http://elderscrolls.wikia.com/wiki/Timeline#4E_29
, sympathizers of the Thalmor in http://elderscrolls.wikia.com/wiki/Valenwood
, the homeland of the http://elderscrolls.wikia.com/wiki/Bosmer
, overthrew the Imperial administration of Valenwood, and joined Valenwood with the Summerset Isles to form the Second Aldmeri Dominion."