Saint Paul, a founding figure of the Christian Church, is pictured with a book and the sword he was martyred by in this oil painting by Batoni.

Christianity struggled to grow—until this skeptic became a believer

The conversion of Paul the Apostle was a watershed moment in Christianity. Here’s how his efforts to spread the faith jumpstarted what is now the world’s largest religion.

Saint Paul, a founding figure of the Christian Church, is pictured with a book and the sword he was martyred by in this oil painting by Batoni.
Image courtesy of National Trust Photographic Library/John Hammond/Bridgeman Images

After Jesus' death in A.D. 33 , his early followers began slowly spreading out from Jerusalem to find sanctuary in places such as Cyrus, Phoenicia, Damascus, and Antioch. The authors of the New Testament, like St. Luke the Evangelist who is believed to have penned the book Acts of the Apostles around A.D. 80, tell the struggles believers and the early church faced in their nascent days. In Acts, Luke tells the story of St. Stephen, the first Christian martyr to be gruesomely executed in A.D. 36. Stephen's stoning, Luke says, prompted other followers to flee so as not to fall victim to similar persecutions. So, what does the Bible say about how this vulnerable faith got jumpstarted, eventually evolving into the world’s most populous religion with some 2.3 billion followers today?

(Biblical stories of Jesus' birth reveal intriguing clues about his times.)

Mystical conversion

Acts of the Apostles tells the story of one man, Saul of Tarsus, who played a huge role in spreading early Christianity. Devoutly Jewish and a Roman citizen, he was an unlikely proponent of this new faith. It describes how he witnessed the mob scene around Stephen’s death, and came to believe it was his solemn duty to persecute Christians, going so far as to drag Christian men and women to prison, punishing them to deny their faith. He obtained permission from the high priest in Jerusalem to pursue and arrest fleeing Christians. On his way to Damascus, Syria, however, a light from heaven flashed around him. He fell to the ground and heard the voice of the resurrected Jesus saying, “Saul, why do you persecute me?” (Acts 9:4). From that moment on, Saul (later called Paul) devoted himself to the Apostolic mission.

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Spreading the message

Among the places where early Christians fled for safety from persecution was Antioch, capital of Roman Syria. The newly converted Paul found himself there and, with the apostle Barnabas, spent a year preaching the gospel and establishing the first Christian church. It was there that the term “Christians”—"followers of Christ”—was coined (Acts 11:21).

It was also from Antioch that Paul embarked on three separate journeys, detailed in Acts, traveling over 10,000 miles between A.D. 46 and 57.  It tells of Paul’s visits to present-day Israel, Syria, Greece, and Turkey, walking roads that Romans built to facilitate control over the empire and enduring uncomfortable passages on weather-exposed decks of boats. Along the way, he argued “persuasively about the kingdom of God” (Acts 19:8), and performed “extraordinary miracles” (Acts 19:11), such as curing the sick. In Cyprus, he baptized a Roman consul, Paulus Sergius. He shared Jesus’ gospel and established churches throughout the Roman Empire, communities of faith that featured confessions, liturgies, bishops, priests, and deacons.

(200,000 miles of Roman roads provided the framework for empire.)

Resistance, arrest, and martyrdom

Everywhere he went, however, Paul also encountered Jewish followers, who called him a heretic. He endured beatings, stoning, and arrests for preaching the gospel.

In Athens, Acts recounts how Paul became distressed over the preponderance of idols. He tried to reason with the citizens: “As I walked around and looked at your objects of worship, I even found an altar with this inscription: To an unknown god. So you are ignorant of the very thing you worship” (Acts 17:23). He debated that this “unknown god” was the biblical God, the creator of heaven and earth. Some sneered, but others said they wanted to hear more from Paul (Acts 17:32). Just by talking to people, he successfully made converts, one by one.

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Acts records that Paul was arrested several times by the Romans and imprisoned twice in Rome. The first time, between A.D. 60 and 62, he was arrested for causing a riot in a Jewish temple in Jerusalem. He was allowed to live in a house, where it’s said he converted his Roman guards.

The Romans arrested him again sometime between A.D. 62 and 67. This time, he was confined to Tullianum, a maximum security prison. Soon after, Paul is said to have been martyred. His end is unclear, but the most common account claims he was beheaded at the order of the Roman emperor Nero, who blamed him as a Christian leader for Rome’s burning.

Paul’s unique ways

Many other apostles and missionaries evangelized Christianity at the same time as Paul. While biblical accounts show that Paul didn't claim to be anything more than an ambassador for Christ, he did have a unique strategy. He worked to baptize souls regardless of whether they were Jewish or Gentile.

One big question centered on whether converts to Christ should also be expected to become Jewish. For the Jerusalem apostles, the answer was yes. For them, faith was inseparable from Jesus’ teachings as a Jewish rabbi. Paul disagreed. He welcomed Gentiles who were attracted to Christianity but were not interested in adopting Jewish customs.

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Paul was intelligent and controversial, pouring his experiences and thoughts into letters throughout his travels. Some say he wrote so many letters because so many people argued with him. Whatever the case, the letters summarize his views on Christianity, ideas that became the bedrock of the Catholic Church. In his Letter to the Romans, for example, he said that faith in Christ supersedes Jewish Law; that each community is part of the “body of Christ” and should be governed by love; and that faith in the Christian God holds the promise of eternal life. In all, he authored 13 epistles (seven of which are undisputedly his, six of which are disputed), making him the most prolific writer in the Bible. Fourteen of the 27 books in the New Testament are attributed to him (though scholars also differ on this number).

Through it all, Paul articulated Jesus’ “kingdom of God” message into an idea that the largely Gentile population could understand and accept and his ability to spread the message of primitive Christianity is truly extraordinary. His three journeys described in Acts permanently established the fledgling faith in Gentile lands and beyond. Without him, the Greco-Roman world might never have heard about the teachings of a charismatic rabbi from Nazareth whose redemptive program went on to embrace the world.

(In Venezuela, a quest for sainthood offers proof of miracles.)

Portions of this work have previously appeared in Jesus and the Origins of Christianity. Copyright © 2016 National Geographic Partners, LLC.
To learn more, check out Jesus and the Origins of Christianity. Available wherever books and magazines are sold

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