The Varangian Guard was an elite unit of the Byzantine Army, from the 10th to the 14th centuries, whose members served as personal bodyguards of the Byzantine Emperors. They are known for being primarily composed of Germanic peoples, specifically, Scandinavians (the Guard was formed 60 years before the end of the Viking age) and Anglo-Saxons from England (particularly after the Norman Invasion).
The guard was first formed under Emperor Basil II in 988, following the Christianization of Kievan Rus' by Vladimir I of Kiev. Vladimir, who had recently usurped power in Kiev with an army of Varangian warriors, sent 6,000 men to Basil as part of a military assistance agreement. Basil's distrust of the native Byzantine guardsmen, whose loyalties often shifted with fatal consequences, as well as the proven loyalty of the Varangians, many of whom served in Byzantium even before, led the Emperor to employ them as his personal guardsmen. Over the years, new recruits from Sweden, Denmark, Norway and Iceland kept a predominantly Norse cast to the organization until the late 11th century.
So many Scandinavians left to enlist in the guard that a medieval Swedish law from Vastergotland stated that no one could inherit while staying in "Greece"- Ã‚Â�the then Scandinavian term for the Byzantine Empire. In the eleventh century, there were also two other European courts that recruited Scandinavians.
Composed primarily of Norsemen and Rus for the first 100 years, the guard began to see increased inclusion of Anglo-Saxons after the successful invasion of England by the Normans. By the time of the Emperor Alexios Komnenos in the late 11th century, the Byzantine Varangian Guard was largely recruited from Anglo-Saxons and "others who had suffered at the hands of the Vikings and their cousins the Normans". The Anglo-Saxons and other Germanic peoples shared with the Vikings a tradition of faithful (to death if necessary) oath-bound service, and after the Norman conquest of England there were many fighting men who had lost their lands and former masters and looked for a living elsewhere.
The Varangian Guard not only provided security for the Byzantine Emperors, but participated in many wars involving Byzantium and often played a crucial role, since they were usually used at the critical moments of a battle. By the late 13th century Varangians were mostly ethnically assimilated by Byzantine Greeks, though the guard operated until at least mid-14th century and in 1400 there were still some people identifying themselves as "Varangians" in Constantinople