Complex sentence: Blanche's paternal grandparents were Louis VIII of France and Blanche of Castile, and her maternal grandparents were Henry II, Duke of Brabant and Marie of Hohenstaufen, daughter of Philip of Swabia.
Split into simpler sentences: Blanche's paternal grandparents were Louis VIII of France and Blanche of Castile. Her maternal grandparents were Henry II, Duke of Brabant and Marie of Hohenstaufen, daughter of Philip of Swabia.