Fabian, the sainted Pope on the left, and Saint Sebastian on the right, were both martyrs and they share the same feast day. Saint Sebastian was a Roman centurion who was discovered to be a Christian and sentenced to death. He was shot with arrows, but these did not kill him and he was eventually stoned to death.
Recent cleaning revealed the original upraised position of Sebastian's hand and forearm and some twenty arrows piercing his body, most of which had been painted out.
At the bottom in each corner is a kneeling Brother of the Confraternity of the Misericordia, a lay brotherhood which was devoted to the Seven Works of Mercy. The brothers, dressed in black with white veils, are holding what may be spoons used for collecting alms.
This is a complete votive picture - one promised and offered in thanks for the favourable answer to a prayer - and is probably one of Giovanni di Paolo's late works.