During the early centuries of the Church, various heresies arose that sought to change the Church’s theology and convert others to the heretics’ own beliefs. A prominent heresy called Donatism was started in the 3rd century. By that time many of the large-scale Roman persecutions had ended, but during some of the earlier tyranny, some Christains had temporarily denied their faith to be spared. Donatism taught that these people could never be readmitted to the Church. 

Although Donatism became a fairly influential heresy, it was nothing compared to Arianism, which at its height had almost as many followers as true Christianity. Arianism was most popular in the 4th century AD, and its doctrine taught that Christ was not equal to the Father and not of the same essence, the Father allows Christ certain divine attributes, and Christ is the agent of creation, but Christ himself is still a creature. Arians were still devoted to Christ, while saying that Christ is not God of His very essence, but that Christ grew to divinity through His own efforts. True Christian doctrine states that Christ is both fully God and fully man, and there is an equal trinity in one God. 

At the Council of Nicea (325), also known as the First Ecumenical Council, Arianism was declared a heresy, but still continued for years after this. Another extremely important event at the Council of Nicea was the establishment of the Nicene Creed, which is basically the Christian confession of faith. In 381 the First Council of Constantinople dealt further with Arianism, added to the Creed, and discussed the Holy Spirit. The Council of Chalcedon in 451 stated that Christ was “two natures, one person.”

Monasticism became a common practice in the early centuries of the Church and is still practiced in modern times. Two different forms of monasticism arose: Eremitic and Cenobitic. Eremitic is a life of absolute isolation as a hermit and Cenobitic is a life in a monastery with other monastics. Eventually most monastics became Cenobitic, and today there are few to little Eremitic monastics. Eremitic monasticism was much more common in the east of the empire while cenobitic was practiced in the west of the empire. Eremitic monasticism often involved penitential regiments, which is the action of discomfort or depriving oneself of food or water for long periods of time. This is also known as “dry martyrdom” because while one doesn’t actually die, they give themselves completely over to God. The practice of monasticism was widely used even after the fall of the Roman Empire and by the 14th century there were 37,000 monasteries. 

Catiline left the city of Rome when he was called out by Cicero, who wanted to justify Catiline’s departure as a conspiracy by identifying members as ethical rebels and economic failures. Giving himself full credit for his work, Cicero stated that the Republic’s survival was at risk and blamed internal enemies like Catiline, adding that Catiline would soon lead an army against Rome. 

Cicero addressed the Senate by alleging that Catiline led an army of scoundrels and wastrels, the conspiracy is made up of losers, and they are all threats to the republic. Arrogantly stating that the gods worked through him, Cicero proclaimed that Catiline would be defeated when he led an army on Rome. However, there were still supporters of Catiline inside the city that needed to be taken care of, persuaded Cicero. 

People who were in debt, immoral, and weak warriors made up Catiline’s army. Cicero urged power to be handed over to him by the Senate because the gods favored Catiline’s defeat. Although the Senate had not yet decided what to do with the conspirators of Catiline, Cicero wanted them to be executed without trial. Knowing that there would be grumblings from the people if the trial did not take place, Cicero spoke to the people in order to identify himself with Jupiter and the Republic. He also reminded them that the Senate had previously honored him, asking only for his good reputation in their minds. 

Announcing to the people the capture of the conspirators, the Senate had given Cicero great honor and he wished only to be remembered for this. In so doing, the Senate had saved the nation, Cicero announced. Because he knew there would be murmurings after the executions, Cicero made several orations in which he explained himself to the people in order to cut short future criticism. Instead of directly calling for their execution, Cicero invoked the gods, citizens, and even slaves, saying all would agree that the conspiracy was totally evil. 

In his first oration, Cicero persuaded Catiline to leave and brought no formal accusation against him, but demonized him. “He has gone, he has departed, he has disappointed, he has rushed out, he is prostrate, stricken, looking back, mourns, vomited out, his followers; dregs of the Republic,” reads the second oration. Cicero used rhetoric, but also five principles which were: Sovereignty: the gods of Rome; Authority: he was the consul who saved Rome; Law: the law of the Senate; Sanctions: death to representative figures of the conspiracy; Succession: the Roman Republic is eternal. In the end, the execution of five men frightened Catiline’s supporters, who fled. Cicero would eventually be murdered by Mark Antony in 42 B.C.

In the early days of Christianity, the Roman Empire did everything it could to destroy the Church. They were unsuccessful, and the spread of Christianity continued under persecution and eventually spread so far that even the emperor of Rome was converted. Although it seems that the Roman Empire hurt Christianity, it could have actually helped, as communication and travel in Rome made preaching and ministry easier. 

The first martyr was Saint Stephen who wasn’t killed by the Romans but by the Jews in 34 AD. This was witnessed by a man named Saul, later called Paul of Tarsus. He was a Jew from Asia Minor and frequently persecuted Christains. On his way to Damascus to find Christains, he was knocked from his horse by a bright light and a voice saying, “Why persecutest thou me?” After this stunning revelation Paul lived in the desert for three years to think and pray, and then returned to Damascus to preach Christ. Former allies of Paul turned against him for this, and he changed his name to Paul instead of Saul. 

After being met with a violent response in Jerusalem, he traveled to Asia Minor to preach to the Gentiles. Paul became a leading figure in the Church and said that the Law of Moses served its purpose, and Christains do not need to keep Jewish law. He continued his missionary trips over 13,000 miles, during which he was frequently arrested. Paul wrote many letters known as “Epistles” to different communities of Christains or individual people. These “Epistles” now compose a large part of the New Testament books of the Bible. Paul was finally martyred for Christ during Nero’s persecution in Rome in 67 AD. 

By the 2nd Century AD, there weren’t as many empire-wide planned killings of Christains, but local ones continued. There was even a statement written by Emperor Trajan that ordered citizens to not investigate Christains, but to only kill them if they admitted to being faithful. That was until the Great Persecution of Diocletian from 303-305 AD during which the eastern part of the Empire was hit particularly hard. After Diocletian stepped down as emperor the persecutions became lighter. In 306 AD, Constantine became the first Christian emperor. He was converted after putting the cross on his soldier’s shields, then winning a great victory. In 313 AD, Constantine implemented the Edict of Milan and Edict of Toleration, stopping all persecutions of Christains and even returned stolen land to Christains.