I recently watched a short Ted Ed video that claimed that the Kievan Rus decided that Slavic Paganism wasnt functional for them enough and decided to convert into another religion and neglected Islam(because of the prohibition of alcohol) and Judiasm(because of their exile of the Holy Land situation) and settled for Orthodox Chrisitianity.
How much truth is there to this? Also what pushed them away from Slavic paganism?
Vladimir called the Great who was the prince at the time allied himself with the Byzantine Empire during a revolt within the Byzantine Empire in the late 900s (A.D.) (no earlier than 980)
As part of a deal for his assistance Vladimir gained a wife, a military alliance and agreed to accept the Orthodox Christian faith.
Like any history of this time period there is debate about exactly what took place and motivation, but if you accept the above as true then his conversion was a practical political choice.
Source, Primary Chronicle
Edit = info added, format.