There are two Murren Artifacts in Fable, and are both incredibly strong. Here is how to get them.

Murren GreatAxe
Found in a Blue Chest, requiring 15 Silver Keys, atop the Hook Coast Lighthouse

Murren Warhammer (My weapon of Choice)
Found as the first chest in the game(unopenable), at the hero's guild, in a blue chest requiring 20 Silver Keys. This weapon has an experience agumentation, so it makes great for upping your stats.