Josiah was slain by Pharaoh Neco of Egypt. But there is an apparent contradiction as to whether he died at Megiddo where the battle was, or later in Jerusalem. This is 2 Kings 23:29-30:
Note carefully the wording of 2 Kings. It does not just say that the fatal blow was delivered in Megiddo (leaving open the possibility that he died later). It says that his servants carried Josiah's dead body from Megiddo back to Jerusalem. By contrast, this is 2 Chronicles 35:23-24:
2 Chronicles seems to say that Josiah was still alive when the chariot reached Jerusalem. The only way out of this problem is to claim that actually, he died during the journey. Does the text of 2 Chronicles allow the possibility that Josiah died in transit? This is not the natural reading - one expects a competent author to write in chronological order - but it's just about possible. I should note though that other Bible translations make it more explicit that Josiah died in Jerusalem. For example, here is the NIV's version of 2 Chronicles 35:24:
The NASB and NRSV translations of 2 Chronicles agree that he died in Jerusalem, in which case 2 Kings is clearly wrong about his dead body being moved from Megiddo.