Heresies and Heretics in Christian History: Century by Century from a Christian View

Series Introduction: Why the Church Had to Guard the Faith

From its earliest days, the Christian Church has carried the responsibility of protecting the truth entrusted to it by Christ and the apostles. This was never optional. Scripture itself calls believers to this task:

• Jude's short letter (1:3, NIV) calls Christians to earnestly defend the faith that was handed down once for all to God's people.
• Jesus warned His followers, "Watch out for false prophets" (Matthew 7:15, NIV).
• Paul told the Ephesian elders that even leaders from among their own number would rise up and twist the truth (Acts 20:30, NIV).
• Paul urged Timothy to "guard the good deposit that was entrusted to you" (2 Timothy 1:14, NIV).

The Church has always taken false teaching seriously — not to be harsh or unloving, but because the truth about Christ, salvation, and the Christian life matters for eternity.

Mistake, False Teaching, or Heresy?

Before starting the series, it helps to understand three things that are often confused with one another:

• A mistake — an honest misunderstanding by someone who loves Christ and His Church. When shown the truth, this person listens and corrects course. This is not heresy.
• A false teaching — an idea that does not match Scripture and the apostolic faith. It may spread for a time but has not yet been carefully examined by the Church's proper authority.
• A heresy — a false teaching carefully examined by the Church's bishops, councils, or recognised authority, and then knowingly and stubbornly held onto even after correction. A teaching becomes heresy not simply for being wrong, but because those who hold it insist on teaching it against the mind of the Church.

Keeping this distinction in mind matters. Many sincere Christians throughout history have made honest mistakes. Only a small number of teachings were ever formally condemned as heresy — and this series will explain, century by century, how and why that happened.

Article 1: First Century Heresies — The Apostolic Age

1. Historical Background

The first century (roughly AD 30–100) was the founding age of the Church. The apostles were alive, the Gospel was spreading rapidly across the Roman Empire, and the New Testament did not yet exist as a single finished book. Christians depended heavily on the direct teaching of the apostles, in person or through their letters, to know what was true.

It was also a turbulent time in the wider world:

• Rome ruled the Mediterranean world, and Christianity was a small, often misunderstood movement within it.
• The Jewish Temple in Jerusalem was destroyed in AD 70, a huge event that reshaped both Jewish and Jewish-Christian life.
• Christians faced growing suspicion and, at times, persecution, including under Emperor Nero in the AD 60s.
• The Church mostly met in homes, without the buildings or organised structures we associate with it today.

With no completed Bible and few settled structures, confusion and false teaching appeared early. The apostles had to respond quickly to protect the young Church.

2. Main Heresies and Errors of This Period

• The Judaizers — Jewish Christians who taught that Gentile believers had to be circumcised and keep the full Law of Moses to be truly saved, in addition to faith in Christ.
• Early legalism — the wider tendency to add human requirements on top of God's grace, as though faith in Christ alone were not enough.
• Early denial of Christ's true humanity — an early form of what would later be called Docetism, suggesting Jesus only "seemed" to have a real body and did not truly suffer or die.
• False teachers within the churches — the New Testament itself (2 Peter, Jude, Revelation) warns of teachers who turned grace into an excuse for sin or introduced strange new doctrines.
• Simon Magus — a sorcerer in Samaria (Acts 8) who tried to buy the power of the Holy Spirit with money and was firmly rebuked by Peter. Later Christian writers remembered him as an early warning about mixing faith with pride and power, and some later tradition linked him to the earliest roots of Gnostic-style thinking, discussed in Article 2.

3. Why These Teachings Were Wrong

From Scripture:

• Paul was astonished that believers in Galatia were turning toward a different message, and warned that anyone — even an apostle or an angel — who preached a gospel contrary to what they had first received should be rejected (Galatians 1:6–9, NIV).
• Paul warned believers to be careful not to be drawn away by clever human ideas and empty philosophy that leave Christ out of the picture (Colossians 2:8, NIV).
• John gives a simple test for true teaching: anyone who denies that Jesus truly came as a real human being is not speaking from God (1 John 4:2–3, NIV).

From apostolic teaching: The apostles, as eyewitnesses of Christ, carried direct authority to define true doctrine. Their united voice, not private opinion, settled disputes — as seen clearly at the Jerusalem Council.

Why it was dangerous:

• If salvation depended on Law-keeping plus faith, Christ's death would not be enough to save — contradicting the heart of the Gospel of grace.
• If Jesus did not have a real, physical body, He did not truly suffer, die, or rise again — removing the very ground of resurrection hope.

4. How the Church Responded

• The apostles and elders gathered in Jerusalem (Acts 15) to settle the Judaizer controversy together rather than leaving it to individuals. After testimony and prayerful discussion, they concluded that Gentile believers did not need circumcision or the full Mosaic Law to be saved.
• Paul personally confronted Peter in Antioch when Peter's actions seemed to support Judaizing pressure (Galatians 2), showing that even respected leaders could be lovingly corrected.
• John's letters directly answered early denials of Christ's true humanity.
• This pattern of apostolic teaching combined with open, prayerful, communal discernment became the model the Church would use for centuries, including at the great councils covered later in this series.

5. What Happened Later

• The Judaizing controversy was formally settled at the Jerusalem Council, but Jewish-Christian legalism did not vanish. A later group known as the Ebionites carried forward Torah-observant teaching combined with a denial of Christ's full divinity, and were rejected by the Church in the centuries that followed.
• The early denial of Christ's true humanity did not fade either. It grew into the fuller Gnostic and Docetic systems of the second century, explored in the next article.
• Simon Magus became, in later Christian writing, a lasting symbol of the danger of mixing faith with pride or personal gain — his name even gave us the word "simony," meaning the buying or selling of spiritual position.

6. Lesson for Christians Today

• Salvation is by grace through faith in Christ, not human effort added on top. Watch for modern versions of "faith plus something else."
• Jesus Christ was, and is, fully human as well as fully God — both truths matter for salvation.
• The apostles and the early Church resolved disputes together, prayerfully and openly, rather than through isolated individuals — a pattern still worth valuing today.
• Not everyone who is mistaken is a heretic. The early Church corrected people like Peter and the Galatian believers with patience, not condemnation, as long as they remained open to correction.

A Coptic Orthodox note: The Church of Alexandria traces its founding to this same apostolic age, through the preaching of St Mark the Evangelist, traditionally dated to the early AD 40s. From its earliest days, the Alexandrian Church placed great importance on carefully guarding and teaching the apostolic faith — a heritage that would later make it a leading centre of Christian learning and a strong defender of the true, full humanity and divinity of Christ in the centuries to come.

7. Short Summary

• The first century was the Church's founding age, guided directly by the apostles.
• The Judaizers taught that Gentile believers needed the Law of Moses plus faith, denying the sufficiency of grace.
• Early denials of Christ's true humanity threatened the reality of His death and resurrection.
• Simon Magus stands as an early warning about mixing faith with pride and personal gain.
• The Jerusalem Council (Acts 15) shows the Church settling disputes together under apostolic authority.
• Not every mistake is heresy — the Church corrected with patience whenever people stayed open and teachable.
• These early errors were the seeds of larger controversies still to come in the centuries ahead.