According to 2 Chron. 18:1, Jehoshaphat “joined affinity with Ahab.” That is, he entered into a formal alliance with him. The alliance was sealed by the marriage of Athaliah, the daughter of Ahab, to Jehoram, the son of Jehoshaphat (2 Kings 8:18, 26; 2 Chron. 21:6). Ahaziah, the son of this union, was presumably named after

 Ahab’s son and heir, and Ahab’s next son seems to have been named after Ahab’s son-in-law, Jehoram, heir to the throne of Judah (see on v. 4). Under the alliance, which evidently was continued by the heirs of Jehoshaphat and Ahab, the members of the royal houses made visits to one another (1 Kings 22:2; 2 Kings 8:29; 2 Chron. 18:1, 2), made a common disposition of their forces in battle (1 Kings 22:4; 2 Chron. 18:3; 22:5, 6), and united in joint ventures for foreign trade (2 Chron. 20:35, 36).