Marduk is the city god of Babylon.
When Babylon became the capital of Babylonia (from about 1500 B.C.), Marduk became more important. Marduk is sometimes called 'Bel' which means 'lord'.
Marduk's symbols are a spade and the Mushhushshu snake-dragon.
In Babylonian mythology, Marduk is called upon to fight an army of demons led by the goddess Tiamat.
He goes into battle when the other gods agree to elect him as their leader. He hunts down Tiamat, kills her and is crowned as the supreme god.
The citizens of Babylon celebrated a New Year festival, during which the king would kneel before a statue of Marduk and vow that he was a good ruler.