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Christian Thinkers 101: A Crash Course on St. Athanasius

St. Athanasius passionately defended Christ’s deity during a time when Christological heresies were rampant, but what else did he contribute to Christianity? Here’s your crash course on the life and accomplishments of St. Athanasius—and why he still matters today.

Who Was St. Athanasius?

St. Athanasius (ca. 296–373) was born and educated in the ancient city of Alexandria. Coming from a Christian family, he would go on to become the greatest theologian of his time. He assisted at the famous Council of Nicea in 325 when the historic Christian church condemned the influential heresy known as Arianism (the view that Jesus was the first and highest creature of God but not fully equal to God—this view is similar to the one advocated by present-day Jehovah’s Witnesses). St. Athanasius later became bishop of Alexandria, a post he held for 46 years, though he was exiled five times for his outspoken opposition to the vexing Arian heresy that continued to gain influence. St. Athanasius was an articulate, tenacious, and untiring defender of Nicene orthodoxy. He argued for the truth of such essential doctrines as the Incarnation and the Trinity.

What Did St. Athanasius Write?

Among several works, St. Athanasius’s two most important apologetics-related books are On the Incarnation and Letters of St. Athanasius Concerning the Holy Spirit. The first book has become a theological classic in which Athanasius explains and defends the doctrine of the Incarnation (Jesus was God in human flesh). In the second work, he both critiques the heretical view that the Holy Spirit is a mere creature and sets forth the orthodox view that the Spirit of God is a full divine person like the Father and the Son.

What Did St. Athanasius Believe?

Christians of various traditions continue to hold several beliefs that St. Athanasius ardently defended. Athanasius’s three most important ideas or arguments for historic Christianity are the following:

  1. St. Athanasius affirmed Nicene orthodoxy and argued that the Son (Jesus Christ) is homoousios (of the “same substance”) with God the Father.
  2. St. Athanasius tied the Incarnation and atonement together in his theological reasoning. He is known for formulating the following theological argument:
    Only God can save people from sin.
    Jesus Christ saves people from sin.
    Therefore, Jesus Christ is God.
  3. At a time when the Arian heresy was at its most influential, the bishops who sided with Arianism taunted Athanasius with the words “The world is against you Athanasius.” But Athanasius defiantly responded: “Athanasius contra mundum” (“No. It’s Athanasius against the world.”). While Arianism insisted that the Son was a mere creature, Athanasius argued for Christ’s full deity.

Why Does St. Athanasius Matter Today?

As an ecclesiastical leader, St. Athanasius has been criticized for allegedly playing politics in his opposition to the Arian heresy, but this claim is short-sighted and he is clearly one of the most honored men in Christian history. He reflects a universal Christian voice in being called the “Father of Orthodoxy” and the “Father of the Canon.” All three branches of Christendom—Eastern Orthodoxy, Roman Catholicism, and Protestantism—revere him. With his strong character and keen theological thinking, St. Athanasius championed Christian orthodoxy at a time when the faith was under its greatest doctrinal assault.

When contemporary evangelicals encounter Jehovah’s Witnesses at their door, they will gain a sense of what Athanasius was up against with the Arian heresy. Evangelicals can learn from Athanasius’s courage and steadfast witness to Christ, the divine-human Savior.

Other articles in the Christian Thinkers 101 series: St. Augustine; C. S. Lewis; Blaise Pascal; St. Anselm; St. Thomas Aquinas; Jonathan Edwards; Søren Kierkegaard; St. Bonaventure; Martin Luther; John Calvin; Irenaeus; Tertullian; St. Basil; St. Jerome; Justin Martyr; Walter Martin; Ronald Nash; Mortimer Adler

Reflections: Your Turn

Athanasius passionately defended Christ’s deity. How does Jesus Christ being both God and man impact his atoning death? Visit Reflections on WordPress to comment with your response.


  • To read his classic work, see On the Incarnation by St. Athanasius.
  • For analysis of St. Athanasius’s life and thought, see A History of Apologetics by Avery Dulles.