Josiah was eight years old when he began to reign
 And must be born when his father was but sixteen, for Amon lived but twenty four years, ( 2 Kings 21:19 ) , 
 and he reigned thirty and one years in Jerusalem;
 and so must die at thirty nine years of age: 
 and his mother's name was Jedidah, the daughter of Adaiah of Boscath;
 a city of the tribe of Judah, (See Gill on Joshua 15:39).