The early Christians, were either Jewish or Gentile converts to Judaism, known to historians as Jewish Christians. Traditionally, the Cornelius, the Centurion, is considered the first converted Gentile. Paul of Tarsus, after his conversion to Christianity, claimed the title of Apostle of the Gentiles. Paul's influence on Christian thought is said to be more significant than any other New Testament author. By the end of the first century, Christianity began to be recognized internally and externally as a religion separate from rabbinic Judaism.
New Testament was developed, with the letters of Paul, the four gospels, and various other works of the followers of Jesus that were also recognized as Holy Scriptures. From Paul's letters, especially from Romans, Christians created a theology based on Christ's atoning work and justification by faith.