:) Nowizard, what does the authenticity of the writings have to do with it?
Firstly, we will never be able to verify this, and secondly, there is no need to verify it. What has come down to us from the history of both Christianity and paganism provides a quite complete picture of both.
I am referring to a much deeper antiquity, about which there is also considerable evidence. In addition, many Orthodox holidays continue to be interpreted in their pre-Christian equivalent: Krasnaya Gorka, Pokrov, Sretenskaya, Maslenitsa, etc.
Ivan Kupala has remained Ivan Kupala:)
Regarding history, any chronicle was written under the direction of the authorities of the respective country. Don't confuse history and reality. In Aztec "history textbooks," the Spanish are pale-faced demons who came with fire and steel, while in Spanish textbooks, the colonists are great explorers. Read Soviet history textbooks, and it turns out that before the Soviet era, there was nothing but worldwide evil:D Bourgeoisie and imperialists!:)