The Norsemen were a North Germanic linguistic group of the Early Middle Ages, during which they spoke the Old Norse language. The language belongs to the North Germanic branch of the Indo-European languages and is the predecessor of the modern Germanic languages of Scandinavia. During the late eighth century, Scandinavians embarked on a large-scale expansion in all directions, giving rise to the Viking Age. In English-language scholarship since the 19th century, Norse seafaring traders, settlers and warriors have commonly been referred to as Vikings. Historians of Anglo-Saxon England distinguish between Norse Vikings (Norsemen) from Norway, who mainly invaded and occupied the islands north and north-west of Britain, as well as Ireland and western Britain, and Danish Vikings, who principally invaded and occupied eastern Britain.

North Germanic peoples, Nordic peoples and in a medieval context Norsemen, were a Germanic linguistic group originating from the Scandinavian Peninsula. They are identified by their cultural similarities, common ancestry and common use of the Proto-Norse language from around 200 AD, a language that around 800 AD became the Old Norse language, which in turn later became the North Germanic languages of today.