The Byzantine empire brought two major items to early Russian culture, written language and Christianity. The current Russian language uses the Cyrillic script, which is developed from the Greek script to a Slavic language. This allows them to move beyond normal runic script and helps them to adopt the religion. This is a split from the rest of the Catholic kingdoms of Western Europe at the time and Russia is the only major modern holdout with Greek Orthodoxy as a majority, in comparison to Poland which is Catholic but still Slavic.
