Apollos helped believers in Achaia.

Acts 18:27-28

27 When Apollos decided that he would like to go to Achaia province, the believers in Ephesus told him that it would be good for him to do that. So they wrote a letter to the believers in Achaia saying that they should welcome Apollos. So Apollos got on a ship to go to Corinth. After he arrived, he greatly helped those whom God had kindly enabled to believe in Jesus. 28 Apollos was vigorously arguing publicly with the leaders of the Jews while many other people listened. By quoting from the Scriptures, he proved to people that Jesus was the Messiah.