The founder of Christianity is Jesus of Nazareth, Paul of Tarsus, or the Emperor Constantine — depending on what you mean by “founded.” Scholars have long recognized that the question of who founded Christianity does not have a single answer. The movement that became the world’s largest religion was shaped across three centuries by figures who played fundamentally different roles: a Jewish preacher who started a renewal movement, an apostle who built its theology and institutional networks, and a Roman emperor who gave it political power.
Each of these figures is essential to the story. None of them, alone, is the whole story.
Jesus of Nazareth: The Movement’s Origin
Jesus of Nazareth (~4 BCE - ~30 CE) was a Jewish teacher and preacher in Roman-controlled Galilee and Judea. He gathered followers, announced the coming kingdom of God, and was executed by crucifixion under the Roman prefect Pontius Pilate around 30 CE.
In the most straightforward sense, he is the founder of Christianity — the person around whom the entire tradition is organized.
But the picture is more complicated than that.
E.P. Sanders, in Jesus and Judaism (1985), argued that Jesus is best understood as the leader of a Jewish renewal movement — not the founder of a new religion. Jesus kept the Sabbath, observed dietary laws, taught in synagogues, and directed his ministry primarily toward fellow Jews. His message about the coming kingdom of God drew on apocalyptic traditions already alive in Second Temple Judaism, a tradition shared by groups like the Essenes and figures like John the Baptist. The historian Paula Fredriksen has similarly emphasized that “Jesus was a Jew, not a Christian.”
Jesus left no written texts. He established no formal institution. He articulated no creed.
What he did was set something in motion — a community of followers who, after his crucifixion, came to believe that God had raised him from the dead. That belief became the catalyst for everything that followed, but it emerged after Jesus’s lifetime, shaped by people who were interpreting his significance rather than executing his organizational plan.
The earliest evidence of that interpretation comes not from the Gospels, which were composed decades later, but from the letters of Paul.
Paul of Tarsus: The Theological Architect
Paul (~5-~64 CE) never met Jesus during Jesus’s lifetime. A Pharisee from Tarsus in Cilicia, Paul experienced what he described as a revelation of the risen Christ and became the movement’s most consequential early advocate. His seven undisputed letters — composed between roughly 50 and 62 CE — are the oldest surviving Christian documents, predating every Gospel by at least a decade.
Paul made three contributions that reshaped the Jesus movement into something approaching a distinct religion.
First, he developed the theology. Paul’s letters contain the earliest written articulations of ideas that would become central to Christianity: that Christ’s death was an atoning sacrifice, that believers are justified by faith rather than by observance of Jewish law, and that the community of believers constitutes a new kind of body — neither exclusively Jewish nor Gentile, but something Paul described as being “in Christ.” These were not ideas he inherited from Jesus’s teaching as recorded in the later Gospels. They were Paul’s theological interpretation of what Jesus’s death and reported resurrection meant.
Second, he opened the movement to non-Jews. The pivotal question in the earliest decades of the Jesus movement was whether Gentile converts needed to adopt Jewish practices — circumcision, dietary laws, Sabbath observance. Paul argued they did not. This position, which generated fierce debate with the Jerusalem community led by James (Jesus’s brother), removed the primary barrier between the movement and the wider Greco-Roman world.
Without this decision, Christianity might have remained a sect within Judaism.
Third, he built institutions. Paul established communities of believers across the eastern Mediterranean — in Thessalonica, Corinth, Philippi, Galatia, and Rome — and maintained them through correspondence, visits, and a network of co-workers. Wayne Meeks, in The First Urban Christians (1983), documented how Paul’s congregations functioned as small, urban, household-based groups that crossed social boundaries in ways unusual for the Roman world.
Some scholars have described Paul as the true founder of Christianity — the person who transformed a regional Jewish movement into a universal religion with its own theology, membership criteria, and organizational structure. Others resist this framing, pointing out that Paul himself always claimed to be interpreting the significance of Jesus, not inventing a new religion.
Constantine: The Imperial Sponsor
Neither Jesus nor Paul made Christianity the dominant religion of the Western world.
That required political power, and the decisive figure was the Emperor Constantine (r. 306-337 CE).
Before Constantine, Christians were a persecuted minority within the Roman Empire. Estimates suggest that by 300 CE, Christians constituted roughly 10 percent of the empire’s population — significant, but far from dominant. The Edict of Milan in 313 CE changed everything by granting Christianity legal recognition and imperial protection. Constantine funded church construction, granted clergy tax exemptions, and convened the Council of Nicaea in 325 CE, which addressed the Arian controversy and produced the Nicene Creed.
Constantine did not make Christianity the state religion — that came under Emperor Theodosius in 380 CE.
But Constantine established the template: a Christianity defined by creeds, enforced by councils, and supported by imperial resources. The institutional structures he enabled — the relationship between church and state, the conciliar model of doctrinal decision-making, the physical infrastructure of basilicas — shaped Christianity for the next seventeen centuries.
If Jesus started the movement and Paul built its theology, Constantine gave it power. The Christianity that emerged from the fourth century was recognizable to Paul in its core claims about Christ, but its institutional character — its wealth, its political influence, its enforcement mechanisms — would have been unimaginable to the apostle who composed his letters from rented rooms and prison cells.
Three Founders, One Question
The question “who founded Christianity?” turns out to be three questions wearing a single mask.
Who originated the movement? Jesus of Nazareth. Who developed the theology and institutional networks that carried it beyond its Jewish origins? Paul of Tarsus. Who transformed it from a persecuted sect into an imperially sponsored religion? Constantine.
Each answer is incomplete without the others.
Remove Jesus and there is no movement. Remove Paul and the movement likely remains a Jewish sect, its message never articulated in the form that would resonate across the Greco-Roman world. Remove Constantine and Christianity might have grown steadily but never acquired the political power that made it the dominant religion of the West.
Larry Hurtado, in Lord Jesus Christ (2003), argued that the earliest Christians’ decision to worship Jesus alongside God — what Hurtado called a “binitarian” pattern of devotion — represented a genuine innovation within Jewish monotheism, one that occurred within the first two decades after the crucifixion. If Hurtado is right, then the seed of what became Christianity was planted very early, in the devotional practices of Jesus’s first followers.
But the plant that grew from that seed was shaped by Paul’s theology, tended by generations of anonymous believers, and eventually transplanted into the soil of Roman imperial power.
The question of who founded Christianity depends, in the end, on what you think a religion is — a set of devotional practices, a theological system, an institutional structure, or all three. The historical evidence suggests: all three, emerging at different moments, through different people, across three centuries.
Christianity’s relationship to Judaism — the tradition from which it emerged — and the places where it first took root add further layers to this founding story. If you want to trace the ideas that shaped Paul’s theology back to the texts he was reading, Uncanon arranges every biblical passage by composition date with scholarly context alongside the text, so you can follow the development of these ideas from the earliest Hebrew writings through Paul’s letters and the Gospels.