People's Crusade
Crosses with firesteels have been used since Roman times, as symbols, but not as coats of arms or emblems. Some historians connect it with the "labarum", the Imperial flag of Constantine the Great (r. 306–337). In the 6th century the cross with four fields (with either letters or heraldry) appear on Byzantine coins. The symbol was adopted by the First Crusaders since the first event, People's Crusade (1096).