Ghosts and Anchors

I apologize if this has been answered before.

I'm creating Hypatia of Alexandria as a ghostly scholar that the mages encounter using RoP:M.

I've figured out most of it I think although I'm having problems finding something. I remember reading in one of the books how ghosts can be anchored by some material item and are forced to haunt around it (In this case, it is the Palla she was wearing when she was murdered). I can't recall which book it was in however and I can't find anything like that in RoP:M

Have any of you used this before and if so, was it a major or minor inferiority?