Flavius Josephus, Antiquities of the Jews
William Whiston, A.M., Ed.

[309] When Zimri, the captain of the army, had killed Elah, he took the kingdom himself, and, according to Jehu's prophecy, slew all the house of Baasha; for it came to pass that Baasha's house utterly perished, on account of his impiety, in the same manner as we have already described the destruction of the house of Jeroboam. But the army that was besieging. Gibbethon, when they heard what had befallen the king, and that when Zimri had killed him, he had gained the kingdom, they made Omri their general king, who drew off his army from Gibbethon, and came to Tirzah, where the royal palace was, and assaulted the city, and took it by force. But when Zimri saw that the city had none to defend it, he fled into the inmost part of the palace, and set it on fire, and burnt himself with it, when he had reigned only seven days. Upon which the people of Israel were presently divided, and part of them would have Tibni to be king, and part Omri; but when those that were for Omri's ruling had beaten Tibni, Omri reigned over all the multitude. Now it was in the thirtieth year of the reign of Asa that Omri reigned for twelve years; six of these years he reigned in the city Tirzah, and the rest in the city called Semareon, but named by the Greeks Samaria; but he himself called it Semareon, from Semer, who sold him the mountain whereon he built it. Now Omri was no way different from those kings that reigned before him, but that he grew worse than they, for they all sought how they might turn the people away from God by their daily wicked practices; and oil that account it was that God made one of them to be slain by another, and that no one person of their families should remain. This Omri also died in Samaria and Ahab his son succeeded him.