Nabonidus was the last king of the Neo-Babylonian Empire, reigning from 556–539 BC. He seized power in a coup, toppling King Labashi-Marduk. He also angered the priests and commoners of Babylon by neglecting the city’s chief god, Marduk, and elevating the moon god, Sin, to the highest status. Nabonidus left the capital for ten years to build and restore temples – mostly to Sin – leaving his son, Belshazzar, in charge. While leading excavations for the restoration effort, he initiated the world’s first known archaeological work.
Meanwhile, the Persian Achaemenid Empire to the east, led by Cyrus the Great, had been gaining strength. King Cyrus had become popular among the residents of Babylon by posing as the one who would restore Marduk to his rightful place in the city. As the Persians advanced to Babylon, Nabonidus returned. He was captured by the Persians in 539 BC and Babylon was occupied, thus ending the Neo-Babylonian Empire. Cyrus was welcomed into the city, where he performed the rites of Marduk. Nabonidus’ fate is uncertain, though it is believed he was exiled to Iran and allowed to occupy a government post.