Task: Explanation
Input (English): William I (c. 1028 – 9 September 1087), usually known as William the Conqueror and sometimes William the Bastard, was the first Norman King of England, reigning from 1066 until his death in 1087. A descendant of Rollo, he was Duke of Normandy (as Duke William II) from 1035 onward. After a long struggle to establish his power, by 1060 his hold on Normandy was secure, and he launched the Norman conquest of England six years later. The rest of his life was marked by struggles to consolidate his hold over England and his continental lands and by difficulties with his eldest son. Question: The Abbey of Saint-Étienne was founded by a descendant of who? Answer: Rollo
Output (English):  A descendant of Rollo, he was Duke of Normandy as Duke William II from 1035 onward.