Prince Charles postponed his wedding because the Pope's funeral is on the same day. He did not want the funeral to parallel such a tragic event.

I'd have to go with the Pope (not in his current condition of course). A head butt with that big hat of his would really do some damage. Of course the dreaded "ear slap" from Prince Charles could be devastating too..................

Oh, I thought this was a hypothetical boxing match up.................. :D

It might have something to do with his being in Rome to represent England at the funeral. This is a duty of monarch's and supercedes his wedding.