I watched another documentary that I didn't mention last night. It was called "The Airmen and the Headhunters". It was super interesting. I'd recommend you watch it too. Oh how I love PBS. I could watch it all day long if it weren't for the overwhelming number of kids shows during the day. But I guess kids deserve public television too.
I was trying to remember what the Labarum was called. I couldn't remember for the life of me. I knew that Constantine used it in battle so I did a google image search for "Constantine's Symbol". The image below was included in the page one results...
