The St. Christopher legend is based on a historical figure, Christopher, who was martyred for his faith by the Roman Emperor Decius in c.250 A.D.
In legend, St.Christopher was a giant who carried the infant Christ across a river. When St. Christopher asked the infant why he felt so heavy, Christ replied that he, Christ, was carrying the sins of the world with him.
In the medieval period (1350-1500), St Christopher was one of the most popular saints, especially for travellers such as pilgrims and merchants. It was believed that seeing an image of the Saint would ensure safety from sudden death for the whole of that day. He became the Patron Saint of Travellers, and his day was July 25th, but he was removed from the Church's calendar of saints in 1969.