The sitter was probably a member of a religious order and, as his habit is grey, he may be a Franciscan. He was first painted holding a book, but the artist later changed this to a scroll.
The frame is original and is carved in one piece with the panel on which the portrait is painted. It appears to have been made by the same carpenter as 'The Virgin and Child in an Interior', also from Campin's workshop, but the pictures were not painted by the same artist.
This is one of the earliest surviving portraits where the subject is resting his fingers on the frame, a device which later became a convention of portraits from the Low Countries.