It represents four Saints: St. John the Evangelist with palm and book; St. John the Baptist with the lamb in a disk; St. Catherine with palm and wheel; St. Margaret issuing from the back of the dragon.
"Virgin and Child enthroned, with owners and their patron saints, preceding Prayer to St. John the Baptist. The man is presented to the Virgin and Child by St. John the Baptist who holds a book with Agnus Dei sitting on top of its cover; the woman in…