Achaia occupies an important place in the history of Paul's missionary work. After preaching in Macedonia and Athens, Paul traveled to Corinth, where he remained for an extended period and helped establish a major Christian congregation. Acts 18 records that Paul was brought before Gallio, the proconsul of Achaia, after opponents accused him of teaching a form of worship contrary to Roman law. Gallio dismissed the dispute as an internal religious matter.
Other New Testament passages show that Christianity spread beyond Corinth within the province. Acts 18:27 describes Apollos traveling to Achaia, while Paul repeatedly refers to the believers of Achaia in his letters. The household of Stephanas is described in 1 Corinthians 16:15 as among the first converts of Achaia. Paul also speaks of Christians in Macedonia and Achaia contributing to the relief of poor believers in Jerusalem.
Achaia therefore represents more than a geographic designation in the New Testament. It was one of the principal regions in which the early Christian movement became established in the Greek-speaking Roman world.