In the very early years of the Soviet Union, religion, specifically, the Russian Orthodox Christian Church, was both banned, as well as the target of wrathful and rabidly anti-religious desecration, discrimination and destruction. For the early Bolsheviks, the Russian Orthodox Church and the Tsar, were essentially, "two sides of the same coin"........in other words, they were viewed to be inseparable and indistinguishable. To the founding generation of Bolshevik Communists, the Tsar and the Church, were Medieval oriented institutions... anachronisms and antiquities that had to be forcibly discarded.
After Lenin's passing, the Soviet Union officially became, an atheistic state whereby religion, in particular, Orthodox Christianity, was officially banned. It was probably an unwise move to have expressed pro religious sentiments in the streets of Moscow, Leningrad or other Soviet Russian cities during much of the 20th century. Yet, despite the official ban, the Russian Orthodox Church did manage to survive and exist within Soviet Russia. In a way, Soviet Russia, never completely extricated itself, nor did it completely disassociate, disaffiliate or divorce itself from the Orthodox Church.
When Mikhail Gorbachev came to power in 1985, his programs were initially designed to liberalize and modernize the old Soviet system-(but not necessarily to universally dismantle it). Both Perestrokia and particularly, Glasnost, were near revolutionary programs-(by traditional Soviet standards) and such a liberalization effort included, the rejuvenation of the Russian Orthodox Church as an active public institution. (Though it really wasn't until after Gorbachev, specifically during the 1990's, that the Orthodox Church experienced a near renaissance in Russia which is present to this day).