2 Chronicles 35:16-19

So at that time the entire service of the LORD was carried out for the celebration of the Passover and the offering of burnt offerings on the altar of the LORD, as King Josiah had ordered. The Israelites who were present celebrated the Passover at that time and observed the Festival of Unleavened Bread for seven days. The Passover had not been observed like this in Israel since the days of the prophet Samuel; and none of the kings of Israel had ever celebrated such a Passover as did Josiah, with the priests, the Levites and all Judah and Israel who were there with the people of Jerusalem. This Passover was celebrated in the eighteenth year of Josiah’s reign.