In a sudden conversion or the fear of destruction, the people of Nineveh believed in God. Notice that they believed in God, not Yahweh, which would have been more difficult. Just like on the boat, Jonah seemed to be successful, even if he was not trying very hard. They proclaimed a fast. Then everyone, no matter whether they were important or not, put on sackcloth to go into mourning.
This appears to be one of the last oracles of Ezekiel. Once again, there is an exact date, the 1st day of the 1st month of the 27th year of King Zedekiah, making it 571 BCE, well after the captivity of Jerusalem. As usual, the word of Yahweh came to Ezekiel, the son of man. Yahweh explained how King Nebuchadnezzar of Babylon had made his army work very hard against Tyre. They were baldheaded and wore out their shoulders. However, neither he nor his army got anything out of Tyre to pay for all the energy that they had spent against it.