St. George and the Dragon.
Finns and Swedes love St. George, whose basic story goes more or less as follows:
There was once a dragon that was terrorizing a town. The townspeople had to give the dragon two sheep per day to keep him satisfied. Then the townspeople ran out of sheep, so they started offering up their children, one per day, as determined by lottery. I think that's a pretty quick jump from sheep to children! Shouldn't they have tried pigs or goats or something first? Dogs?
Anyhoo, one day the lot fell to the king's daughter (aka, the princess)!
That's when St. George came wandering by and was like, oh heck no, it was fine when the dragon was eating peasant babies, but not the princess! TOO FAR. So he slayed the dragon, on the condition that everyone convert to Christianity. And everyone (except the already-sacrificed children) lived happily ever after.