Viking raid warfare and tactics
Vikings were members of tribes, originally from Scandinavia, of Norse ancestry, who gained a reputation for their raids and piracy in many parts of Europe, especially England, Ireland, and Frankish territories. The term "Viking Age" refers to the period roughly from 793 AD to the late 11th century in Europe. In this era Viking activity started with raids on Christian lands in England and eventually expanded to mainland Europe, including parts of present-day Russia. While maritime battles were rare, Viking bands proved very successful in raiding coastal towns and monasteries due to their efficient warships, and intimidating war tactics, skillful hand-to-hand combat, and fearlessness. What started as Viking raids on small towns transformed into the establishment of important agricultural spaces and commercial trading-hubs across Europe through rudimentary colonization. Vikings' tactics in warfare gave them an enormous advantage in successfully raiding (and later colonizing), despite their small population in comparison to that of their enemies.
Norse activity in the British Isles
The first known account of a Viking raid taking place in Anglo-Saxon England comes from 787, when three ships from Hordaland (in modern Norway) landed in the Isle of Portland on the southern coast of Wessex. They were approached by the royal reeve from Dorchester, whose job it was to identify all foreign merchants entering the kingdom, and they proceeded to kill him. It is likely that other raids (the records for which have since been lost) occurred soon after, for in 792 King Offa of Mercia began to make arrangements for the defence of Kent from raids perpetrated by "pagan peoples".