Duccio's Maesta

Rear view - Predella
Incident in the life of Christ.

The first image on the predella is lost. Logic would tell us that it would show the baptism of Christ, as this immediately precedes the accounts of the temptations of Christ in Luke chapter 3. 
Some scholars argue for two further missing scenes, from the sides of the predella. These could show the Baptist pointing at Christ (Behold the Lamb of God, which taketh away the sins of the world -  John 1 v29) and  Christ in the wilderness. 
  This image below is not by Duccio: it is Giotto's version of the baptism, from the Arena chapel in Padua. It may give some idea of the lost image of the Maesta. 

        Maesta rear index