The Abbey of Saint-Étienne was founded by a descendant of who?
Abbey of Saint-Étienne, Caen:  It was founded in 1063 by William the Conqueror and is one of the most important Romanesque buildings in Normandy. William the Conqueror:  A descendant of Rollo, he was Duke of Normandy (as Duke William II) from 1035 onward.
i don't know