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.
Longship
During the Viking Age (900-1200 AD) Vikings were the dominant seafarers of the North Atlantic. One of the keys to their success was the able to navigate skillfully across the open waters.The Vikings were experts in judging speed and wind direction, and in knowing the current and when to expect high and low tides. Viking navigational techniques are not well understood, but historians postulate that the Vikings probably had some sort of primitive astrolabe and used the stars to plot their course.