Complex sentence: Her paternal grandparents were Frederick I, Holy Roman Emperor and Beatrice I, Countess of Burgundy, and her mother's parents were Byzantine Emperor Isaac II Angelos and his first wife Herina Tornikaina Charles Cawley, "Medieval Lands", Byzantium (1057-1204).
Split into simpler sentences: Her paternal grandparents were Frederick I, Holy Roman Emperor and Beatrice I, Countess of Burgundy. Her mother's parents were Byzantine Emperor Isaac II Angelos and his first wife Herina Tornikaina Charles Cawley, "Medieval Lands", Byzantium (1057-1204).