North Germanic peoples
Vikings were also active in Francia. Some of these Vikings would sail through the Strait of Gibraltar and pillage the coasts of the Mediterranean Sea. In the early 10th century, a group of Vikings under the leadership of Rollo settled in Rouen, France, and established the Duchy of Normandy. The descendants of these Vikings, known as the "Normans", would in the 11th century conquer England, Southern Italy, and North Africa, and play a leading role in launching the Crusades. Sub-groups of the Normans include Anglo-Normans, Scoto-Normans, Cambro-Normans, Hiberno-Normans and Italo-Normans.
Viking expansion
The Vikings pillaged monasteries on Ireland's west coast in 795, and then spread out to cover the rest of the coastline. The north and east of the island were most affected. During the first 40 years, the raids were conducted by small, mobile Viking groups. From 830 on, the groups consisted of large fleets of Viking ships. From 840, the Vikings began establishing permanent bases at the coasts. Dublin was the most significant settlement in the long term. The Irish became accustomed to the Viking presence and culture. In some cases they became allies and also intermarried.