Why was Ivan the Terrible not allowed into the church?
The Orthodox Church condemned multiple marriages and even recorded their maximum number in the collection of decisions of the Stoglav Council, which took place in 1551. According to these documents, laymen could marry a maximum of three times. “The first marriage is the law, the second is forgiveness, the third is a crime, the fourth is impiety, because it is a swinish life,” the text of the Stoglav stated. A two-year penance (that is, punishment) was imposed for the second marriage. A five-year one was imposed for the third. The “serial spouse” faced a ban on visiting the church for four years and receiving communion (participation in the sacrament during which believers receive bread and wine symbolizing the body and blood of Christ) for ten years for his fourth marriage. There were, of course, mitigating circumstances. But, in any case, remarriages were viewed poorly.
Despite this, Ivan the Terrible still decided to marry a fourth time, to Anna Koltovskaya. And he even received permission from the church, claiming that, due to the sudden death of his third wife Marfa Sobakina, their marriage remained platonic. But, the punishment for this was still severe: The tsar was forbidden to enter the church for a year, he could receive communion only on Easter and then he had to stand with the penitents for another year.
However, this marriage also turned out to be hasty: less than six months later, Anna was forcibly tonsured as a nun. And for his subsequent marriages, Ivan the Terrible no longer asked anyone's permission.