My brothers, it always especialy hurts when bother harm/beat brother... from the micro level (from angle of one single family) to the macro level (when we speak about kin people/nations).
What does it matter who is Catholic, who is Protestant or Orthodox, etc. It is even good to us that we can expirience different religious approach thru expiriance of our kin nations.
Togather we can do so much, divided we are easy target
But Roman empire, for example, was not so invincible, as it is described in textbooks.
Tell us more please, about Russian expiriances with Romans. What remembered old chronicles?