Complex sentence: Her paternal grandparents were Jean de Laval and Jeanne du Perrier, and her maternal grandparents were Jacques d'Aillon and Jeanne Madeleine de Vendôme, Dame d'Illiers.
Split into simpler sentences: Her paternal grandparents were Jean de Laval and Jeanne du Perrier. Her maternal grandparents were Jacques d'Aillon and Jeanne Madeleine de Vendôme, Dame d'Illiers.