Sadko is the principal character in a Russian medieval epic bylina. He was an adventurer, merchant, and gusli musician from Novgorod.
Sadko, Palekh miniature
Sadko in the Underwater Tsardom by Ilya Repin.
A bylina is a type of Russian oral epic poem.
Dobrynya Nikitich rescues Zabava Putyatichna from the dragon Gorynych, by Ivan Bilibin
Mikula Selyaninovich and Volga Svyatoslavich with his druzhina.