Final answer:
The Corinthian church was established by the Apostle Paul in the city of Corinth.
Step-by-step explanation:
The Corinthian church was established by the Apostle Paul according to Acts 18. Paul traveled to the city of Corinth, which was a significant Greek and Roman city in the ancient Mediterranean world. In Corinth, Paul encountered the religious and cultural experience of the Greco-Roman world, and he spread Christianity to the people of Corinth.