An important missionary who spread Christianity was Paul the Apostle , a first‑century Jewish follower of Jesus who traveled widely through the Roman Empire preaching, teaching, and starting new churches.

Who Paul the Apostle Was

  • Paul (originally named Saul of Tarsus) was a Jewish Pharisee who, according to Christian tradition, converted after a dramatic encounter with the risen Jesus on the road to Damascus.
  • After his conversion, he became one of the most active early Christian leaders, writing letters that later formed a significant part of the New Testament.

How Paul Spread Christianity

  • Paul undertook several long missionary journeys around the eastern Mediterranean—through regions like Asia Minor (modern Türkiye), Greece, and possibly as far as Rome—founding and strengthening Christian communities.
  • He focused on preaching not only to Jews but also to Gentiles (non‑Jews), which helped Christianity move from a small Jewish sect to a broader, multiethnic faith across the Roman world.

Why Paul Is Considered Important

  • Many historians and theologians see Paul as one of the key architects of early Christian theology, especially ideas about salvation by faith and the inclusion of Gentiles.
  • Because of his extensive travels, church planting, and influential writings, he is often described as one of the most important missionaries in Christian history.

TL;DR: A widely recognized answer to “who was an important missionary that spread Christianity?” is Paul the Apostle , whose travels, preaching, and letters were central to the early growth of Christianity in the Roman Empire.