What happened after Christianity became the national religion of Roman Empire?

Answer 1

A few of the things that happened soon after Theodosius made Christianity, "as taught by the bishops of Rome and Alexandria" (Trinitarian Christianity) the state religion of Rome in 380 or 381, and as a direct result of that decision:

• the public worship of the pagan gods was banned;
• the possession of private statues of the household gods was banned;
• Augury and the divination of entrails became capital offences, and even non-enforcement of the law was itself a serious offence;
• those Pagan feast days that had not yet been rendered Christian ones were declared ordinary working days;
• The Church considered itself authorised to desecrate and plunder the pagan temples and appropriate them for Christian use, without any of the partial restrictions that had previously applied;
• Theodosius decreed, "All writings whatever which Porphyry or anyone else has written against the Christian religion, in the possession of whomsoever they shall be found, shall be committed to the fire," an edict that quickly came to be used against all writings not found useful to the Christian religion;
• Thousands of pagans from all sides of the empire suffered martyrdom in the Christian death camps;
• In 396, a new edict declared paganism to be high treason in the Eastern Empire;
• Mob lynchings of non-Christians broke out in 401 CE.
• The Olympic Games were no longer held;
• Arian Christians were persecuted.