This painting illustrates the story of Cadmus, founder of the ancient city of Thebes, as told in Ovid’s Metamorphoses. Cadmus is slaying the dragon that has killed his companions while on a journey to Thebes. They have died trying to collect spring water from the dragon’s cave, on the left, not knowing that it is sacred to the god Mars. Cadmus is protected by a lion-skin and armed with a javelin.