Kalitki are tiny Karelian pasties made of unfermented dough with rye flour. They are usually served with tea and baked with different filling: millet, potato, cottage cheese, oat flour, barley...
Karelians also call them "ryupittetyu" that means "puckered" as they actually look like.
The fact that they are made of unfermented dough definitely means that they were baked long before the Conversion of Russia, apparently they appeared in the IX century and maybe even earlier.
However, despite their long history, they have been actually made only in Karelia. Their recipe has never inspired Russians who believe that pastries always should be fresh, puffy, smelling sweet. And kalitki are made of plain rye flour, filled with pearl barley and after baking they become hard as iron and are to be softened again.