Ahaziah, Athaliah and the Hidden Heir

"Forty and two years old was Ahaziah when he began to reign, and he reigned one year in Jerusalem. His mother's name also was Athaliah the daughter of Omri. He also walked in the ways of the house of Ahab: for his mother was his counseller to do wickedly."

"And the destruction of Ahaziah was of God by coming to Joram." Jehu kills the princes of Judah. "And he sought Ahaziah: and they caught him, (for he was hid in Samaria,) and brought him to Jehu: and when they had slain him, they buried him: Because, said they, he is the son of Jehoshaphat, who sought the LORD with all his heart."

"But Jehoshabeath, the daughter of the king, took Joash the son of Ahaziah, and stole him from among the king's sons that were slain… (for she was the sister of Ahaziah,) hid him from Athaliah." "And he was with them hid in the house of God six years: and Athaliah reigned over the land."

42 or 22

The Hebrew of 22:2 says 42, which would make Ahaziah older than his father; 2 Kings 8:26 says 22; the library's Greek of Chronicles says 20. See the 2 Kings passage page.

Two accounts of his death

Chronicles: found hiding in Samaria and killed; 2 Kings 9:27: shot near Ibleam, died at Megiddo. See the 2 Kings passage page.

Jehoshabeath the priest's wife

Only Chronicles says Jehosheba was Jehoiada's wife, explaining how she could hide the child in the temple.