» This article is about the year 911 A.D.. For the emergency telephone number, see 9-1-1. » For the attacks in the United States, see September 11, 2001 attacks For other uses, see 911 (disambiguation). Events By Place Europe Autumn — Charles the Simple agrees to the Treaty of St.-Claire-sur-Epte, ceding the lower Seine area to the Norse and Norman invaders under Rollo, the first Duke of Normandy. The town of Drogheda, Ireland is founded by the Danes. Prince Oleg of Novgorod raids the… (More on 911)