Mary's soul is represented by the small figure in white, the color of rebirth in baptism. The angel on the right is waiting to accept the soul and take it to Heaven. Other early Dormitions show the soul already in the angel's hands. As in Imperial ceremonies when gifts are given or received, the angel's hands are covered with a cloth.
The tearful person bending over Mary's body does not have wings, so he is probably St. John the Evangelist, the one apostle who is most often represented without a beard. The reclining body is dressed in the Virgin's usual blue mantle with a star where it covers the forehead.
I neglected to record this photograph in my field notes. The date and time recorded by the camera would be when we were in Sant'Apollinare Nuovo in Ravenna, which would date the mosaic to the 6th century. But the style seems later, so it is possible that the camera date/time was erroneous. A date before the 10th or 11th century is suggested by the angel who will carry the soul to Heaven, and by the cloth on his hands. In the later centuries in the West it is Christ himself who takes his mother up, and hands with gifts go uncovered.
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Photographed at the basilica by Richard Stracke, shared under Attribution-NonCommercial-ShareAlike license.