mandylion

The tradition of the sacred image is related to established prototypes […] handed down in Christian art, the most important [of which] is the acheiropoietos ("not made by human hands") image of the Christ on the Mandilion. It is said that the Christ gave His image, imprinted on a piece of fabric, to the messengers of the King of Edessa, Abgar, who had asked Him for His portrait. The Mandilion had been preserved at Constantinople until it disappeared when the town was pillaged by the Latin Crusaders. A copy of the Mandilion is preserved in the cathedral of Laon.