The Top Ten Most Important Church Councils

To be deep into history, John Henry Newman wrote, is to cease to be a Protestant. Put another way, to be deep into history is to become stronger in the Catholic faith—something we are all called to do in this Year of Faith.

To make that journey into the history of our faith is to discover anew its most basic tenets. Who was Jesus really? How can God be three persons in one being? What is the proper role of the Church in salvation? And how does Mary fit into all this?

These questions, and many more, were raised and answered in the ecumenical, or universal, Church councils.

Ironically, one key to understanding the orthodox teachings of these councils is heresy. The councils, especially the earliest ones, were essentially anti-heresy conventions, called to sort the wheat of dogma from the chaff of heresy. This could be a dizzying and disorderly process: no sooner had one bastion of orthodoxy had been defended, than the Church had to rush to the defense of another. So, while one council had to correct heretics who falsely divided Christ into two persons, the next council had to make a course correction in the other direction, reining in heretics who falsely united His human and divine natures into one.

“To have fallen into any one of the fads from Gnosticism to Christian Science would indeed have been obvious and tame,” G. K. Chesterton wrote in Orthodoxy. “But to have avoided them all has been one whirling adventure; and in my vision the heavenly chariot flies thundering through the ages, the dull heresies sprawling and prostrate, the wild truth reeling but erect.”

In all, there were 21 ecumenical councils. All were important in their time, but only some of them stand out for the lasting significance they have had on the faith and life of the Church today. Here, then, are the top ten must-know councils, listed chronologically by the date they were convened:

1. First Council of Nicaea, 325:

One of the earliest heresies to rear its head was Arianism, which asserted that Christ was created by the Father and later adopted as His Son. Refuting this heresy—by declaring Christ one in being with the Father—was the chief task of the Council of Nicaea. In the process, the Nicene Creed was born. 

2. First Council of Constantinople, 381:

This council defended dogma on two fronts. It affirmed the divinity of the Holy Spirit as the third person of the Trinity. And it condemned a new heresy that claimed Christ was part man and part God but not completely one or the other. Instead, the heresy, known as Apollinarism, put forward the harebrained theory that Christ was comprised of a human body and a divine mind.

3. Council of Ephesus, 431:

This council defined the dogma that Christ is one person, not two persons, as the heretical Nestorians claimed. This council also has the distinction of being the only ecumenical gathering that made any dogmatic statements about Mary, declaring her to be the Theotokos, or Mother of God. The other great achievement of this council is its least known: repudiation of one of the most insidious of heresies in Christian history—Pelagianism, which denied original sin and said men can use their free will to attain salvation on their own merits, without God’s grace.

4. Council of Chalcedon, 451:

After Ephesus declared that Christ was one person, some Christians took that teaching too far, concluding that He also had just one nature, a mystical blend of the human and divine (this heresy was known as Monophysitism, from the Greek words for one and nature). That obviously throws a wrench in the entire message of the gospel. If Christ wasn’t fully man, had mankind really been redeemed? If He wasn’t fully divine, had God really saved us? Needless to say, the Church quickly pulled together another council to clarify its earlier teaching: Christ was one person, but had two natures. The council ended up achieving more than it bargained for, in ways good and bad. On the upside, it helped to cement the primacy of the Pope as the leader of the Church. But it had the tragic and unintended consequence of sending the Orthodox churches in Syria, Egypt, and Ethiopia into schism.

5. Third Council of Constantinople, 680:

This council squashed a new heresy about Christ called Monothelitism, which held that Christ had just one will. You may be thinking—now we’re really getting into the weeds, aren’t we? But Monothelitism was a serious heresy that was a throwback to Monophysitism (the heresy that Christ had one nature). In saying Christ had one will, the Monothelites were essentially saying he had one nature. In rejecting this heresy, this council closed a major chapter in Church history, putting to rest any major lingering debates over who Christ was.

6. Second Council of Nicaea II, 787:

This council declared that venerating icons was not only permissible, but also necessary. And it lambasted anyone who claimed that veneration was akin to worship of God or that veneration of icons violated the Old Testament commandment against worshipping false idols. Protestants who repeat such accusations today could use reminding that this controversy was settled centuries ago.

7. Fourth Lateran Council, 1215:

By all accounts, this was an epic council. Both St. Dominic and St. Francis attended; a Holy Roman Emperor was named; and the council helped launch a new crusade. In matters of strictly faith and morals, its achievements were equally staggering: the council defined the doctrine that there is no salvation outside the church, approved the use of the term transubstantiation, mandated that Christians go to confession at least once a year, and  condemned the erroneous Trinitarian teachings of Joachim of Fiore, calling them heretical and “insane.”

8. Council of Florence, 1431:

This council is important for two apparently unrelated reasons. First, it decided what books belong in the Bible. Second, it made a heroic attempt to reunite Catholic Church with the Eastern Orthodox Greek churches that had broken off several hundred years earlier. But the reunion was short-lived—almost immediately dissolving after the council ended.

9. Council of Trent, 1545:

It’s hard to imagine a more influential council. Trent defined and defended a whole swath of Church dogmas and teachings about the Eucharist, the authority of the Church, the role of Scripture, and the nature of the Sacraments. The council also led to a standardized Mass, launched the Counter Reformation, and inspired the baroque movement in the arts. In short, Trent gave Catholicism its definitive shape and substance for the next half millennium—at least, up until Vatican II. (But that’s another story. 

10. Vatican I, 1869:

Although it had been an article of faith since the earliest times, it wasn’t until Vatican I that the Church defined the dogma of papal infallibility. Two criteria were put in place: the Pope had to be speaking in an official capacity, that is, from the chair, or cathedra, of St. Peter and he had to be speaking about matters of faith and morals. Since that council, there has been only one infallible papal statement, in 1950, on the Assumption of Mary. (The other commonly cited ex cathedra statement, on Mary’s Immaculate Conception, was in 1854.)

Why Vatican II didn’t make the list:

Obviously, Vatican II looms the largest of all the councils not only because it was the most recent one but also because it brought sweeping changes to the Church. The significance and salience of those changes remain a subject of controversy and confusion—and therefore the lasting impact of Vatican II is unclear. If those changes mark the beginning of a new course for the Church—whatever that might be—then Vatican II will go down as a pivotal moment. But history has yet to render its verdict.

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Stephen Beale is a freelance writer based in Providence, Rhode Island. Raised as an evangelical Protestant, he is a convert to Catholicism. He is a former news editor at and was a correspondent for the New Hampshire Union Leader, where he covered the 2008 presidential primary. He has appeared on Fox News, C-SPAN and the Today Show and his writing has been published in the Washington Times, Providence Journal, the National Catholic Register and on and A native of Topsfield, Massachusetts, he graduated from Brown University in 2004 with a degree in classics and history. His areas of interest include Eastern Christianity, Marian and Eucharistic theology, medieval history, and the saints. He welcomes tips, suggestions, and any other feedback at bealenews at gmail dot com. Follow him on Twitter at

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