Frank:
They've found Viking 'graffiti' in Constantinople. Given that the Volga River dumps out into the Black Sea, it stands to reason that the Vikings navigated the entire shoreline.
I tend to think of these operations as "armed trading" missions. If you are weak/evenly matched, you trade. If you are strong, you take (raid). Either way the Viking wins.
Excepting in the Days of Yore, when the high-school football team from Gothenburg, Nebraska, collided with the high-school football team from Cozad.
The Gothenburg team was called the "Vikings."
The Cozad team was called the "Haymakers."
In this pigskin instance, the Vikings always got stacked.