— Sir William Temple, 1st Baronet
As early as the 6th century, the North Germanic tribes were actively engaged in naval raids on
Continental Europe. Between 512 and 520, as attested in the Royal Frankish Annals and Anglo-Saxon
poem Beowulf, Hygelac, King of the Geats, made a great raid in the Rhineland. Carrying off great booty,
Hygelac was defeated and killed before he could return to Scandinavia. Before the 7th century AD,
Norwegian seafarers had settled Shetland.[66] During this time the Frisians were the foremost rivals of
the Scandinavians for naval supremacy in the North Sea.[67] By the 8th century, the Swedes, by far the
most advanced of the North Germanic peoples, had established colonial settlements
in Estonia, Latvia and the southern shores of Lake Ladoga and Lake Onega in Russia.[68][69] The settlement
of Grobiņa in Latvia and the Salme ships of Saaremaa, Estonia, are testimony to this expansion. In this
period the entire eastern Baltic Sea came to be dominated by a homogenous warrior culture derived
from Sweden, in which Old Norse served as the lingua franca.[70]
Viking Age
Main article: Viking Age
Map showing area of Norse settlements during
the Viking Age, including Norman conquests
In the late 8th century North Germanic tribes embarked on a massive expansion in all the directions.
This was the start of the Viking Age, which lasted until 1066 AD. This expansion is considered the last of
the great North Germanic migrations.[23] These seafaring traders, settlers and warriors are commonly
referred to as Vikings .[16][36][71][72][73][74][75] The North Germanic peoples of the Viking Age as a whole are
sometimes referred to as Norsemen.[6][15][17][76][77][33][13][37][36][74][38][78][39][18][34] However, the
term Norsemen is often used only for early Norwegians,[19][79] or as a synonym for Vikings.[13] Though the
early Scandinavians did not have an ethnonym for themselves, they certainly had a common identity,
which has survived among their descendants up to the present day.[14]
The cause of this expansion is often thought to have been overpopulation.[80][71] Other explanations
include political tensions, disruption of trade with the Abbasid Caliphate, or vengeance
against massacres committed against the pagan Saxons by the Carolingian Empire.[7] The prospect of a
Carolingian invasion of Denmark itself created much fear and resentment among the
Scandinavians.[81] The destruction of the naval powers of the Frisians by Charlemagne in the 8th century
also probably played a key role in facilitating the naval dominance of the Scandinvians.[67] The
centralization of power that was carried out by Harald Fairhair and other powerful Scandinavian rulers
drove many warlike men into exile abroad.[82] By this time North Germanic military units were typically