Marduk's career tracks the rise of the city of Babylon. He begins as a local god of that city, of no special rank in the older Mesopotamian pantheon headed by Anu, Enlil and Ea (Enki). As Babylon grew from a minor town into the capital of an empire, above all under Hammurabi in the eighteenth century BCE and again under the Neo-Babylonian kings a millennium later, its god was promoted to match, until he stood at the head of the gods. This is one of the clearest cases in the ancient world of theology following political power, and Mesopotamian scribes did not hide the process; they wrote it into their myths.
By the first millennium BCE Marduk was often called simply Bel, "the Lord", the same title behind the biblical Bel, and his great temple-tower, the ziggurat Etemenanki at Babylon, is widely thought to lie behind the biblical Tower of Babel. His main temple was the Esagila.
He is imagined as a storm- and warrior-god armed with the winds and the thunderbolt, and later also as a god of wisdom and incantation, inheriting the magical expertise of his father Ea. His star was the planet we call Jupiter.