The Vikings (meaning North men) were the last of the barbarian tribes called Germans by the Romans to terrorize Europe. Spreading out from their homelands in Scandinavia, they struck suddenly across the seas from their dragon boats (called such because of the dragon heads carved on the bow and stern).
Being pagan, they did not hesitate to kill churchmen and loot church holdings, and they were feared for their ruthlessness and ferocity. At the same time, they were remarkable craftsmen, sailors, explorers, and traders.
The Viking homelands were Norway, Sweden, and Denmark. They and their descendants controlled, at least temporarily, most of the Baltic Coast, much of inland Russia, Normandy in France, England, Sicily, southern Italy, and parts of Palestine. They discovered Iceland in 825 (Irish monks were there already) and settled there in 875. Some people think that the Vikings reached Newfoundland and explored part of North America 500 years before the voyage of Columbus.