Ashur-dan III was king of Assyria. He was king when the prophet Jonah ran away from God, but got swallowed by a big fish. Three days later, the fish spit out Jonah. Jonah then went to Nineveh and preached repentance to the Assyrians. Ashur-dan III, who was the king at that time, ordered everyone to mourn and cry out to God to save them from the coming judgement foretold by Jonah. God heard their cry and saw their repentance and relented from destroying them.