And found a certain Jew named Aquila, born in Pontus, lately come from Italy, with his wife Priscilla; (because that Claudius had commanded all Jews to depart from Rome:) and came unto them.
Note 2 at Ac 18:2: Aquila was a Jew, born in Pontus (see note 3 at this verse), who had been living in Rome with his wife, Priscilla. After being expelled from Rome, they came to live in Corinth where they met Paul on his first visit to Corinth. They were tentmakers by trade, as was the Apostle Paul, so Paul lived with them during his stay in Corinth (18 months, Ac 18:11).
Aquila and Priscilla left Corinth with the Apostle Paul and went with him to Ephesus (Ac 18:18-19), remaining there even after Paul left for Jerusalem. While in Ephesus, Aquila and Priscilla encountered Apollos (see note 1 at Ac 18:24), who was eloquent and mighty in his teaching of the Scriptures, but he didn't have a full revelation of the Gospel. Aquila and Priscilla were grounded enough in the Scriptures to explain "the way of God more perfectly" (Ac 18:26) unto Apollos.
Paul included a salutation from Aquila and Priscilla to the Corinthians in his first epistle to that church (1Co 16:19). This epistle was written from Asia (1Co 16:19), probably from Ephesus, where Aquila and Priscilla were residing. Paul later sent greetings to Aquila and Priscilla, who lived in Rome at that time, saying that they were his helpers who had "laid down their own necks" for his life (Ro 16:3-4). Paul also spoke of the church that met in their home in Rome.
Still later, they must have moved back to Ephesus, because the Apostle Paul again sent greetings to Aquila and Priscilla when he wrote his second epistle to Timothy while Paul was imprisoned in Rome (2Ti 4:19).
Note 3 at Ac 18:2: The name Pontus means "a sea" (Strong's Concordance). It was the region occupying the eastern half of the Asia Minor coast of the Black Sea. The Black Sea was originally called Pontos Euxeinos, from which the name Pontus was derived. When conquered by the Romans around 63 B.C., the province of Pontus was merged with the province of Bithynia (see note 5 at Ac 16:7) to form the single province of Pontus and Bithynia.