The elite Byzantine military unit that recruited many Scandinavian and Rus warriors was the Varangian Guard.
The Varangian Guard served the Byzantine emperor as a heavily armed household force and personal guard. Its members came especially from Scandinavia and the lands associated with the Rus, and later recruitment also included Englishmen after the Norman conquest of England.
The force became prominent during the reign of Emperor Basil II. In 988, Prince Vladimir I of Kyiv sent warriors to Constantinople as part of an agreement connected with his alliance and marriage to Basil’s sister Anna. These northern soldiers helped the emperor defeat a rebellion and strengthened the guard’s reputation.
The Varangians were valued for loyalty to the emperor and became associated with large axes. They were not identical to all Viking warriors: “Varangian” was a broader Byzantine term for Scandinavian or Scandinavian-connected people active in the east.