Any of the Vikings, or Norsemen, who settled in northern France (or the Frankish kingdom) and their descendants. As pagan pirates from Denmark, Norway, and Iceland, they raided the European coast in the 8th century. They settled in the lower Seine valley by c. 900. In 911 they were granted territory around what is now Rouen by King Charles III and then extended their territory westward. They founded the duchy of Normandy, governed by a line of rulers who called themselves counts or dukes of Normandy. Though the Normans converted to Christianity and adopted the French language, they continued to display their Viking ancestors' recklessness and appetite for conquest. In the 11th century they seized England in the Norman Conquest and colonized southern Italy and Sicily. The Normans also participated in the reconquest of Spain and in the Crusades, and the Normans of Italy and Sicily were rivals of the Byzantine emperors.