The raids and conquests of the Vikings, the Scandinavian warriors also referred as Norsemen, Northmen, Danes or Normans took place from the end of the 8th to the 11th century. The causes for sudden expansion of the Vikings are mostly unknown but the majority of scholars assumes that overpopulation, internal dissension, and quest for trade and adventures were the main reasons for their expeditions.
The Viking expansion predominantly took place by sea and rivers. Their ships known as the longships were notable for being long and narrow and having a high prow as well as for being very fast. The longship had two methods of propulsion, oars and sail, and had an average crew of 50 men. There were several types of longships which varied from the purpose and period.
The Viking raids started with an attack on the island of Lindisfarne off the east coast of England in 793. Over the following decades, the Viking raids in the English coast became more frequent while the Anglo-Saxon Kingdoms were unable to repulse the invaders. The Vikings started to settle in England in the middle of the 9th century and reached an agreement with the Anglo-Saxon kings in 886 which resulted in the creation of an independent Viking settlement in England known as the Danelaw. The Anglo-Saxon kings returned the territory of Danelaw under their rule i the 10th century but the Vikings conquered England under leadership of Danish prince, Canute the Great who was crowned King of England in 1016. The Viking rule in England collapsed in 1042, while the English crown returned to the Saxon royal family which meanwhile lived in exile. However, in 1066 England was conquered by William the Conqueror, a descendant of the Viking leader Rollo who settled in Normandy and became the first Duke of Normandy in 911.
The Vikings also settled in Ireland, isles north of Scotland, Iceland, Greenland and even reached North America, while numerous local kingdoms arose in northern Europe which became the precursors of the kingdoms of Denmark, Sweden and Norway.
The Vikings represented a great threat to the western part of Frankish Empire in the 9th century. They penetrated deep into the Frankish territory down the rivers Loire, Seine and Garonne, besieged Paris several times and began to settle in the valley of the lower Seine River at the end of 9th century. Charles III the Simple who was not able to repulse the Vikings decided to put an end to the Viking raids by reaching an agreement with the Viking leader Rollo in 911. With the Treaty of Saint-Clair-sur-Epte, Charles III ceded the Vikings the territory which came to be known as Normandy, while Rollo converted to Christianity. The Vikings in Normandy eventually converted to Christianity, abandoned piracy and raiding, and adopted the French culture and language. Their descendants, the Normans conquered England in 1066, captured Sicily from the Saracens in 1061, Apulia and Calabria from the Byzantine Empire and established themselves as an important European power.
Viking quest for trade routes in Eastern Europe also played a major role in the establishment of Kievan Rus in the 9th century. The establishment of the Kievan Rus is attributed to the Swedish Vikings, the Varangians who built their trade bases in the Baltic and penetrated deep into today’s Russia, Belarus and Ukraine.