"The young man saith unto him, All these things have I kept from my youth up: what lack I yet? Jesus said unto him, 'If thou wilt be perfect, go and sell that thou hast, and give to the poor, and thou shalt have treasure in heaven: and come and follow me.' But when the young man heard that saying, he went away sorrowful: for he had great possessions." (Mt 19:20-22)
I understand that the items in question are stolen, this has been stressed to the limit. But to the Catholics under Rome, these things are now a part of their history as well, they have been there for generations upon generations (which I understand does not legitamise keeping things, but just trying to make a feeble point). If you were told that everything that you have inherited from your family; your grandparents' heirlooms, even your home and any treasures and things you hold of great esteem and such, were all stolen property, how fast would you return it? Then say you're the Pope of Rome and have now incurred the guilt of the stolen property without having done any of the stealing to begin with. It must be a hard position to be in, is all I'm saying.