The news reached the king of Nineveh, and he arose from his throne, and took off his royal robe, covered himself with sackcloth, and sat in ashes.
As for the quibble that Jonah did not include the name of the king of Nineveh, it should be observed that it was not in his style of writing to include such personal designations.  He did not give the name of the ship, nor of the captain with whom he sailed, nor any one of a dozen other things that would have satisfied human curiosity.  This is after the manner of holy writers throughout the Bible.