Complex sentence: For many centuries of the Third Age, many Haradrim were still ruled by Black Númenórean Lords, or further north by the Kings of Gondor, but ultimately, Harad fell under the influence of Mordor, for much of the Age.
Split into simpler sentences: For many centuries of the Third Age, many Haradrim were still ruled by Black Númenórean Lords, or further north by the Kings of Gondor. But ultimately Harad fell under the influence of Mordor for much of the Age.