I seem to recall that since Morrowind and Oblivion's late 3rd Era period, the Empire once held control over all of Tamriel, unless I am mistaken. If not on a local level, at least on a provincial level as a whole, and every one of them was subject to be ruled by the Emperor. When did the Empire lose control over Summerset Isles, Valenwood, Elsweyr, and Black Marsh? I know that Morrowind was invaded by the Argonians, but wouldn't it follow that they had to declare war against the Empire to begin with? Did the Empire control Morrowind during that time, as well, or were the Dark Elves independent? I also know that Hammerfell had declared independence at some point, but I want to know under what circumstances that occurred; the province was invaded by the Thalmor, yet did the Empire give it up as an independent state, or did they hand it directly to the Thalmor?