Josiah means in the bible: 1 King of Judah 641-610 B.C. 2 Kgs. 22-24; 2 Chr. 34-35. He was still young and under Hilkiah’s guidance, made a complete religious reformation that reached the northern tribes. He rebuilt the temple and destroyed the high places and idolatrous images, brought down the priests who were worshipping idols and held a huge Passover 2 Kgs. 23:21-23. Hilkiah 2Kgs discovered a book on the law during this reformation. 22:8-9; 2 Chr. 34:15-16. This made a huge impression, and resulted in the centralization of all sacrifice worship at Jerusalem as well as the elimination of any local idolatrous high places or sanctuaries. Josiah was involved in the Assyria-Egypt war and Pharaoh Necho denied enmity. Josiah encountered him at Megiddo battle and defeated 2 Chr. 35:20-25. See also 2 Kgs. 23:29-30; Jer. 22:10-12, 18; Zech. 12:11.
(in Bible Dictionary)