By the later 300s AD, the Roman emperors were all Christians. So more and more of the people of the empire converted to Christianity. One of the most important men who encouraged people to convert was Ambrose, the bishop of Milan in northern Italy. Ambrose worked hard to define what sort of relationship Roman emperors would have with the Christian church. Ambrose (AM-broze) insisted that even Roman emperors had to do what the church told them to do. Otherwise the emperors would go to hell when they died and burn forever. The emperors, who were used to being treated like gods themselves, did not like this idea. But in the end Ambrose found ways to force them to do what he told them to do.
This was how they fought it out: in the 380s AD, the emperor Theodosius heard a lawsuit brought by some Jews. The Christian bishop of that Roman town had told his followers to go and burn down the Jewish synagogue. Sure enough, the Christians had burned down the synagogue. The Jews appealed to Theodosius for justice. After he heard the case, Theodosius said that the bishop should pay to rebuild their synagogue. But Ambrose wrote to Theodosius and said that was wrong, because Christian money shouldn’t be used to pay for Jewish things.
Theodosius still thought that it was right to pay for what you had broken. So Ambrose threatened to not let anybody in Milan take Communion until Theodosius let the bishop off. He would excommunicate them all. And in the end, Theodosius did let the bishop off (though he punished the Christians who had actually burnt down the synagogue).
Soon after that, Ambrose and Theodosius had another fight. Some people in Thessaloniki, in northern Greece, had murdered some Roman soldiers who were acting as security guards. They were just angry because their favorite charioteer wasn’t going to be in the horse race they had come to see. Theodosius was angry that people had attacked Roman soldiers and killed them, and he wanted to teach them a lesson. He ordered that all the people at the races on a certain day should be killed to pay them back. And Roman soldiers did go and kill all those people, even old people and children who hadn’t done anything – seven thousand people altogether.
Well, a lot of those people in Thessaloniki were Christians. Thessaloniki had had Christians for a long time, because it was one of the places that Saint Paul went to when he was converting people. When Bishop Ambrose heard about these Christians being killed, he was very angry himself. He told the emperor Theodosius that he had to say he was sorry, in public, for killing those people, before he could go to heaven anymore. Ambrose said he would excommunicate Theodosius if he didn’t apologize. Theodosius really didn’t want to say he was sorry, but finally Ambrose made him do it.
Ambrose was also one of the teachers of Augustine.