Board Thread:Lore Discussion/@comment-86.24.50.100-20130623082136/@comment-1600847-20140825204839

Well they did exist as of 3E 433, and no mention is made of the Mythic Dawn killing the Shornhlem royal family, only Uriel's 3 sons and Uriel himself.

But as I said, it's quite vague. I'd be surprised if Bethesda's lead writer for the TES games even knows about this little snippet :P