I've been curious about this for awhile and so far have found little information so I thought I'd post about it here. I've seen it in a number of old films, most notably It's a Wonderful Life. Does anyone know the history behind wearing a black arm band for mourning? How long is it usually worn? Is it primarily associated with a certain faith? Has anyone here ever worn one? Any ideas on what material it is, or where someone would get one?