darje,
we could start a big debate here...the chicken or the egg...but really, the Cyrillic alphabet was brought up North to Russia (which wasnt even exacly Russia at the time - Kievskaya Russ/Moskovskye Knizhestvo/etc) from the lands of Bulgaria ( which was aready Bulgaria at the time) where Cyril (from whose name Cyrillic come from) and Methodius [two brothers] and their deciples had settled after they were kicked out of Moravia (today's Czech) where they were on a missioin from the Byzantine Empire to educate the common village people (slavic), give them an alphabet, translate the bible for them - so they can be christians
... history in very short