The government then passed to his son Josia. He is related to have been very pious, and to have attended to divine things with the utmost care, profiting largely by the aid of the priest Helchia. Having read a book written with the words of God, and which had been found in the temple by the priest, in which it was stated that the Hebrew nation would be destroyed on account of their frequent acts of impiety and sacrilege, by his pious supplications to God, and constant tears, he averted the impending overthrow.
When he learned through Olda the prophetess that this favor was granted him, he then with still greater care set himself to practice the worship of God, inasmuch as he was now under obligation to the divine goodness. Accordingly, he burned all the vessels which had by the superstitions of former kings been consecrated to idols. For to such a height had profane observances prevailed, that they used to pay divine honors to the sun and moon, and even erected shrines made of metal to these fancied deities.
Josia reduced these to powder, and also slew the priests of the profane temples. He did not even spare the tombs of the impious; and it was observed that thus was fulfilled what had of old been predicted by the prophet. In the eighteenth year of his reign, the Passover was celebrated. And about three years afterwards, having gone forth to battle against Nechao, king of Egypt, who was making war upon the Assyrians, before the armies properly engaged, he was wounded by an arrow. And being carried back to the city, he died of that wound, after he had reigned twenty and one years.
Source: Sacred History (New Advent)