“Ahaziah the son of Ahab began to reign over Israel in Samaria the seventeenth year of Jehoshaphat king of Judah, and reigned two years over Israel.”
King James Version (KJV)
22:51 Ahaziah, &c. - Ahaziah was made king by his father, andreigned in conjunction with him a year or two before Ahab's death, andas long after it; even as Jehoram the son of Jehoshaphat was madeking by his father in his life - time, which possibly was done in compliancewith Ahab's desire upon marriage of his daughter to Jehoshaphat'sson; and it may be Ahab, to induce him to do so, give him an exampleof it, and made his son his partner in the kingdom.