Kiev'n Rus
What Russia was originally called during it's "led by viking kings" era. It was called Kiev'n Rus because of its capital being Kiev and the slavs there being called the "rus" which eventually evolved into Russia. Kiev'n Rus was formed when viking warlords wanted to expand their kingdoms, and some powerful vikings decided to go more east. There, the slavic people were glad since for a lot of time they didn't have a leader, but now with the vikings, they could crown a king, or more specifically a grand duke which is how Kiev'n Rus came to be.
Hey Khan, I heard of this place called Kiev'n Rus which is just on our borders, think we should invade? I mean, what are the chances a bunch of horseless slavs could defeat our armies of tens of thousands?