The shroud, depicting the Entombment, is placed on the altar to symbolize the winding-sheet of Christ and is used during the procession of the Burial of Christ on the Saturday before Easter, the central Festival of the Orthodox year. The form was adopted from the Byzantine epitaphios, which itself evolved in the 14th century from the aer placed over the vessels containing the Sacramental Bread and Wine, symbols of the Sacrificial Death of Christ.

Liudmila Likhacheva, Gates of Mystery, The Art of Holy Russia