Simplify the following text for a Grade 11 native English-speaking person.
Original: Nabopolassar was followed by his son Nebuchadnezzar II , whose reign of 43 years made Babylon once more the mistress of the civilized world , including the conquering of Phoenicia in 585 BC .
Simplified: The king Nebuchadnezzar II , whose reign of 43 years made Babylon once more the mistress of the civilized world , conquered Phoenicia in 585 BC .