The reach of the Scandinavian Vikings was enormous. Besides terrorizing the Western European coast, they also headed all the way to Constantinople (modern day Turkey), which was at the time the capital of the Eastern Roman Empire, also called the Byzantine Empire.
Here they served in the Varangian guard, an elite unit guarding the Byzantine Emperor.
In the image they are depicted on top of a building with axes in their hands.
"The Great World History Book"