Complex sentence: Her paternal grandparents were John of Brienne, King of Jerusalem, Emperor of Constantinople, and Berenguela of Leon, and her maternal grandparents were Geoffrey VI, Viscount de Chateaudun and Clémence des Roches.
Split into simpler sentences: Her paternal grandparents were John of Brienne, King of Jerusalem, Emperor of Constantinople, and Berenguela of Leon. Her maternal grandparents were Geoffrey VI, Viscount de Chateaudun and Clémence des Roches.