Saint Christopher by Hieronymus Bosch, circa 1480.
Saint Christopher is the man of legend, first described in 6th century Greece and becoming very popular across Europe by the 9th century.
He was said to be a veritable giant who sought to serve the mightiest of leaders. When he learned that the king of Canaan feared the devil, he joined a band of bandits led by a man who called himself the devil. But when Christopher learned that this devilish man actually lived in fear of Christ, the huge man was sought the ways of Christianity.
His mentor was a hermit who told Christopher to fast, but the big man found it too difficult. So his mentor told him to perform the service of carrying travelers across a particularly treacherous river.
One day a child asked to be carried across. Midway through the rapids, the child became unbearably heavy and when Christopher complained upon reaching the other shore, the child told him: "You had on your shoulders not only the whole world, but Him who made it. I am Christ your king, whom you are serving by this work." Then the child vanished.
From the 6th century on, Saint Christopher became known as the protector of travelers. Often portrayed with a child on his shoulder and a staff in his hand, paintings of him became popular in churches throughout Europe, and in England were outnumbered only by paintings of the Virgin Mary.