Board Thread:Lore Discussion/@comment-2.100.91.236-20130823111402/@comment-25323290-20140826061525

Basically, the Red Mountain erupted (which is the largest volcano in Tamriel) and destroyed Vvardenfell which is the centre island of Morrowind. The Argonians took this as a chance to get revenge on the Dark Elves for enslaving their kind a long time ago, and invaded southern Morrowind. Because of this, many Dark Elves are fleeing to the small island of Solstheim and Skyrim to escape the terror that awaits them in Morrowind.