The Cairo in the History of Rome Dot Com

The cairo was a well known good luck symbol in the ancient world before constantine was allegedly commanded painted on his soldiers' shields. The dual meaning of cairo meant that christians could see what they wanted to see, and pagans can see what they want to see without stepping on each other's toes. Eusebius then continues with his version of the lactantius story, that on the night before the battle, constantine was visited by christ himself, who told him to use the cairo as a symbol of power against his enemies. This prompted stantine to create the labarum, a military standard that featured the cairo atop a more traditional cross.