1 Kings 22:41

And Jehoshaphat the son of Asa began to reign over Judah in the fourth year of Ahab king of Israel.

Cross References

2 Chronicles 20:31 And Jehoshaphat reigned over Judah: he was thirty and five years old when he began to reign, and he reigned twenty and five years in Jerusalem. And his mother's name was Azubah the daughter of Shilhi.
1 Kings 22:2 And it came to pass in the third year, that Jehoshaphat the king of Judah came down to the king of Israel.
1 Chronicles 3:10 And Solomon's son was Rehoboam, Abia his son, Asa his son, Jehoshaphat his son,
2 Chronicles 17:1 And Jehoshaphat his son reigned in his stead, and strengthened himself against Israel.