In the fifteenth year of Amaziah, the son of Joash king
 of Judah, Jeroboam the son of Joash king of Israel began to reign
 in Samaria
 So that he reigned fourteen or fifteen years contemporary with him; for Amaziah reigned twenty nine years: 
 [and reigned] forty and one years;
 Josephus says F9 forty, giving only the round number.