בִּשְׁנַת֩ שְׁלֹשִׁ֨ים וְאַחַ֜ת שָׁנָ֗ה לְאָסָא֙ מֶ֣לֶךְ יְהוּדָ֔ה מָלַ֤ךְ עָמְרִי֙ עַל־יִשְׂרָאֵ֔ל שְׁתֵּ֥ים עֶשְׂרֵ֖ה שָׁנָ֑ה בְּתִרְצָ֖ה מָלַ֥ךְ שֵׁשׁ־שָׁנִֽים׃
In the thirty and first year of Asa king of Judah began Omri to reign over Israel, and reigned twelve years; six years reigned he in Tirzah.
Read midrashic interpretation of I Kings 16:23: and classical rabbinic exegesis.