The archangel Michael appears as a winged knight in armour slaying the devil, in the form of a dragon. This subject, from the Biblical Book of Revelation, was popular in southern Spain, where it was associated with the 'reconquista', the recovery of Spanish territory lost to the Moors in the Middle Ages. The panel was probably the centre of a larger altarpiece. The artist's interest in sumptuous patterns is especially evident in the treatment of the saint's armour and cloak, and in the decorative punching, describing the his halo and enriching the gold background.