This question raises three distinct controversies about whether Viking actually achieved an advantage, what method was used to achieve this objective, and the motivation behind it. In order to conduct effective analysis, it is necessary to decide an appropriate evaluation period. On the contrary, E Roesdahl suggests that Viking "800 years before the BCE" and "entering the 11th century" has played a "decisive role" in many parts of Europe. It is important to examine the opposition faced by Viking, but there is no doubt the evidence that they have achieved a dominant position in the ocean.
From the oldest recorded 790's attack to the British 1066 Norman conquest, it was often called the Viking era of Scandinavian history. Viking used the Norwegian Sea and the Baltic Sea as the southern sea route. The Normans were descendants of Viking and received a feudal rule in the northern part of France - Normandy region in the 10th century. In this respect, the descendants of Viking continue to influence in Northern Europe. Likewise, King Harold Goldwinson who was King of the last Anglo-Saxon in the UK owned an ancestor of Denmark. The two Vikings were on the throne of England. There, Suwinn Falkbeard declared the British throne from 1013 to 1014, and his son Knut Great became the king of England 1016 - 1035
In the history of Scandinavia, the era of Britain's Norman conquest from the late 8th century to 1066 was called the Viking era. Medieval Viking used the Baltic Sea and the Norwegian Sea as the southern sea route. Geographically, the Viking era was assigned not only to Scandinavia but also to the territory of North Germanman. Viking set a new land north, south, and east. As a result, an independent village was established in the Shetland Islands, Iceland and Greenland. They also set up a short settlement in Newfoundland about 1000 years ago. Viking was the first person to discover these lands and calm down. Every previous explorer was blown away when they were pursuing these areas, or while watching them from afar.
In 830, Ross of Sweden landed on the south coast of the Black Sea. There Emperor Byzantine landed Viking from the Mediterranean to Francia. Strangely, these special vikings clearly experienced this painful experience of crossing the slab territory and they feared that they would come back in the same way and grasp the opportunity for Emperor Byzantine to have mercy. Indeed, the impression of terror is so great that no longer Ross Viking no longer recorded adventure in Slavic land to visit Constantinople in the next few decades.