No, of course Kiev was founded by the Swedes. Right. Okay, so trade was hugely important to Kiev. Almost all of their wars ended with trade concession treaties, and their law codes were unusually devoted to the subject of commerce. The Rus traded raw materials like fur, wax, and also slaves. We're not going to venture into the astonishingly intense etymological debate over whether the word Slav derives from the Latin word for slave, because there is nothing more terrifying and verbose than an etymologist's flame war. But yeah, the Rus traded slaves.