Silus Vesuius is an Imperial Mythic Dawn fanatic and historical expert. He takes a particular interest in Mehrunes Dagon. He lives in and operates a museum inside his home in Dawnstar, which features a number of Mythic Dawn artifacts, including all four tomes of the Mythic Dawn Commentaries and a tattered page from the Mythic Dawnarxes. One display case also contains a full set of Mythic Dawn apparel, robes with and without hood, gloves and shoes. The robes give a 75% faster magicka regen effect.
Silus claims to be the descendant of the one of the Mythic Dawn cult members who slew Uriel Septim VII in the Imperial City Sewers during the Oblivion Crisis.
If you kill him inside his museum and steal all the artifacts, you may be attacked by a hired thug carrying a contract from him, presumably a glitch .