Complex sentence: Her paternal grandparents were King David I of Scotland and Maud, Countess of Huntingdon, and her maternal grandparents were William de Warenne, 2nd Earl of Surrey and Elizabeth of Vermandois.
Split into simpler sentences: Her paternal grandparents were King David I of Scotland and Maud, Countess of Huntingdon. Her maternal grandparents were William de Warenne, 2nd Earl of Surrey and Elizabeth of Vermandois.