2 Kgs 21:1

בֶּן־שְׁתֵּ֨ים עֶשְׂרֵ֤ה שָׁנָה֙ מְנַשֶּׁ֣ה בְמָלְכ֔וֹ וַחֲמִשִּׁ֤ים וְחָמֵשׁ֙ שָׁנָ֔ה מָלַ֖ךְ בִּירוּשָׁלִָ֑ם וְשֵׁ֥ם אִמּ֖וֹ חֶפְצִי־בָֽהּ׃

Manasseh was twelve years old when he became king, and he reigned in Jerusalem fifty-five years. His mother’s name was Hephzibah.