1. It was the first ecumenical council since the Council of Jerusalem in Acts.
This would be the first council concerning the entire Church on earth in almost 300 years. There had been plenty of “synods,” smaller councils and meetings of bishops and church leaders that made decisions for their local divisions and church communities, but a council that would make a decision binding to the entire Church on earth had not been held since the meeting in Acts where the Apostles gathered to decide whether the Gentiles had to become Jews in order to become Christians (they decided they didn’t).
2. It was called by the “Christian” Emperor Constantine, but probably not for the reasons you think.
In 312 AD Constantine won the Battle of Milvian Bridge which secured the Imperial Throne for himself. He declared himself a Christian and supported the previously illegal faith, co-signing the Edict of Milan in 313 AD making Christianity a legal religion among the many accepted in Roman culture. Contrary to popular belief, he did not make Christianity the state religion. That would not happen until the Edict of Thessalonica in 380 AD long after Constantine’s death.
Constantine called the council in 325 AD with one goal in mind: unity. The Church at this time was heavily divided along many fronts but none were as divisive as the one over the nature of Christ Himself. Was He God? Was He a god? Was He something in between these things? The debate created a clear divide in the Church and even at times lead to violence. If Constantine, the Emperor, was to be a Christian, then Christianity needed to be united. In other words, the Church was making Constantine look bad. Contrary to popular belief, Constantine honestly didn’t care what the council decided. He told them to come to an agreement and he would back up whatever they agreed on, regardless of what it was. He technically presided over the council because he was the head of state but he did not take place in the debates or the decisions.
3. The Council did not discuss the doctrine of the Trinity.
Most people think the Council created the doctrine of the Trinity. It didn’t. The only concern of the council of this kind was over the nature of Christ and His relationship to the Father. It did not involve the Holy Spirit at all and the total relationship was not a point of discussion. The debate of the Trinity as a whole would be decided later at the Council of Constantinople in 360 AD. The concept of the Trinity was however already in place. We have records referring to the Godhead and the Trinity as far back as the 2nd Century.
4. The debate over the nature of Christ was almost over before it began.
The main debate and issue facing the council was the nature of Christ. The two major views of the day were between the traditional view of Christ as God incarnate and those promoted by Arius that Christ was merely God’s greatest creation.
Arius’ argument was that Christ was the first creation of God. He was neither of the same substance as God, nor shared God’s eternal nor divine nature. He claimed Jesus was the best and brightest of God’s creations, but a creation nonetheless. Much of Arius argument hinged on passages that refer to Jesus being “begotten” or “firstborn of creation” as well as “the Father is greater than I.”
The traditional view stemmed from the idea that any Son begotten by the Father must by definition be of the same substance and nature. Therefore, the Father and Son were always Father and Son, eternally. They are co-equal and co-substantial. They argued that Christ was begotten eternally, that is He has no beginning or end. To believe otherwise, they said, destroyed the unity of the Godhead because Christ would be unequal with the Father. Supporting scriptures for this view include “I and the Father are one” and “the Word was God.” They declared that the Son was equal to God in all aspects and is eternally derived from the Father, a declaration made earlier by Athanasius.
Arius came with roughly 22 supporters in tow. Considering that approximately 300 bishops were in attendance, this was not a negligible following, but also clearly in the minority. To make matters worse for Arius, almost all of his supporters abandoned him when the implications of his views were made plain to them.
The Council declared that the Son was truly God Himself, that He was of the same substance as the Father and existed with Him eternally. They argued this doctrine best fit the Scripture’s presentation of Christ as the Son as well as fitting with the traditional beliefs handed down by the Church fathers and Apostles.
Arius along with just two others refused to agree with the council’s decision. The emperor exiled them.
5. But that didn’t end the matter…
As much as Constantine wanted his Christianity wrapped up in a neat bow, it just wasn’t to be. The debate continued just as hotly after the council as it did before, and many violent protests would see Christian blood spilled in the streets. After a time, Arius relaxed some of his more heretical claims (but never renounced them) and was permitted to return from exile, when he promptly died while trying to take a poop. (No seriously) The movement declined afterwards but never totally went away, and many sects today (ex. Jehovah’s Witnesses) adhere to many of the same claims as Arius did.
6. The Council also addressed the Meletian Schism and Christian Apostates.
During the reigns of particularly nasty emperors in Rome, Christianity was heavily persecuted. Few could match the persecution under Diocletian, when Roman soldiers went door to door interrogating suspected Christians and throwing any who did not renounce Christ in prison. Many of those arrested were later executed. There were some Christians who “lapsed” under this stress and denounced Christ in order to save their lives. Once the crisis was over, many Christians who had endured prison and torture for their faith did not want to let these “apostates” back into the Church. Of these, none were as unforgiving as Bishop Melitus.
Melitus made it clear in his province that no apostates were to be forgiven or allowed back into the Church. Other bishops in the area were soon following his example. This deeply concerned other bishops across the Empire who felt this refusal to forgive was anti-Christian and should be addressed.
The council voted and agreed that these lapsed Christians should be forgiven if they sought it and allowed back into the Church. They also agreed that since Melitus was an unforgiving jerk, being a bishop might not be his thing, so they told him his schism could rejoin the Church if he handed in his vestments and his bishops would have to reapply to keep their positions. Melitus refused which would have created quite serious problems later on had Melitus not died soon after. The schism died with him.
7. One of the big issues on the docket was Easter.
The Easter debate is a complicated one. To be brief, where Easter fell depended on when Passover fell, and since Passover on the Jewish Lunar calendar moved around, this produced a problem for Romans who used the solar Julian calendar. In addition, many Church scholars believed the computations by the Jewish scholars were wrong and that the original Easter was on a different date. Most were moving to fix a date based on the best possible data to the actual original Easter, but some still felt that since it was linked to a Jewish holiday, Easter should follow the Jewish calendar.
Eventually they voted to calculate what day Passover would have been at the time of the Crucifixion, and fixed Easter relative to that date on the solar calendar. What they didn’t do was actually do that. They left it for another time, and it didn’t actually get done for centuries.
8. They voted on a number of other, weird issues.
The council had a laundry list of sundry items that were bugging the Church leadership. Two of the more interesting ones were problems the Church itself had created. In the wake of the Apostolic Era (where the Apostles we know and love called all the shots), the next generation of Church leaders began to ferment some strange interpretations of their forebears writings. In particular were the puzzling instructions in 1st Corinthians 7 where Paul seems to be both for and against marriage.
A movement thus began starting in the Second Century declaring that marriage was, in fact, not a good thing. Well, it wasn’t the best thing certainly. Christian leadership began a cult of celibacy that touted lifelong celibacy as the greatest path and led a man or woman the closest to Christ. Marriage was for the carnal, the weak people who couldn’t control themselves. Real Christians stay celibate for life.
Pretty soon though, men who really loved Jesus and didn’t want to fail Him found celibacy to be unbearable. Knowing that marriage was a cop out, these men did what they had to keep it real with Jesus.
They castrated themselves.
In addition to the rampant castrations (which usually just killed the men rather than rendering them eunuchs) there were spiritual marriages. You see, another insane way to read the end of 1st Corinthians 7 is to twist Paul’s words in such a way that he seems to be suggesting that men and women move in together and live celibate lives together as unmarried virgins. These shack-ins were called spiritual marriages and were hailed by the celibacy cult as the ultimate form of Christian perseverance. I mean there you are, living together with temptation right within reach, but never grasping it all for the glory of God! And it totally worked!
Whatever noble intentions they may have begun with, these spiritual marriages often turned into real ones once the pregnancy began to show. This was obviously a bad idea that only encouraged sexual sin, not prevented it. Not surprisingly, the council reached a decision to ban self castration and banned members of the clergy from entering into spiritual marriages. Not long after the council, another ruling banned them altogether.
9. They laid the foundation for the Papacy.
The council also voted to grant several new and exclusive powers to the bishops of Rome and Alexandria, recognizing those bishops as having special authority over the two major centers of the Church at that time. While the bishop of Alexandria would eventually decline in power along with the Empire, the bishop of Rome would only grow in power and authority until he had almost complete autonomy over the entire Church. You might better know the bishop of Rome by his pet title today: the Pope.
10. They did not decide on the canon of the Bible.
In fact, no council ever made that decision. The canon (or books accepted as the inspired word of God in the Bible) was actually already set by the end of the Second Century. During the actual time of the Apostles and just afterwards, it was just a known fact which manuscripts were the work of the Apostles and their disciples and which weren’t. A decision set in stone wasn’t needed. It would be like a council having to be called today to decide which writings belong to Thomas Jefferson and which belonged to Karl Marx. It’s just a no brainer. By the time of the Nicaean council in the Fourth Century, the Bible was long since a done deal. It is true that shortly after the council, Constantine commissioned some fifty complete Bibles (containing the OT and NT) to be scribed and bound for use in the major churches. These Bibles are widely believed to be the first bound books to contain all of Christian scripture.