In 988 Prince Svyatolslav who was the Rurikid Main Man at the time decided to eradicate Paganism which was causing all sorts of divisive issues. He needed to find a mainstream religion that could be applied across Russia and hopefully unite the many tribes competing to be the Boss.
The Story goes that he considered a short list of Western and Middle Eastern religions – Judaism was considered but as they didn’t eat Pork that was rejected. Next he considered Islam as they practised polygamy which he liked the idea of, but then they shun alcohol so that went out of the window. Catholicism – No way too much guilt !
At the time Russian relations with Byzantium were strained so that didn’t work and he decided to adopt his own version of Greek Orthodoxy which with some modifications has survived to this day.
Russian Orthodoxy is about the only thing that the average Russian has had to hold onto over past millennium and continues till this day. Hence the vast number of Cathedrals, Churches, Chapels and Monestaries most which are operational every day.
Anyway I digress as we are heading to Kostroma and its f-ing bridge !!