Corinth

a Grecian city, on the isthmus which joins the Peloponnesus to the mainland of Greece. It is about 48 miles west of Athens. The ancient city was destroyed by the Romans (B.C. 146), and that mentioned in the New Testament was quite a new city, having been rebuilt about a century afterwards and peopled by a colony of freedmen from Rome. It became under the Romans the seat of government for Southern Greece or Achaia (Acts 18:12). It was noted for its wealth, and for the luxurious and immoral and vicious habits of the people. It had a large mixed population of Romans, Greeks, and Jews. When Paul first visited the city (A.D. 51 or 52), Gallio, the brother of Seneca, was proconsul. Here Paul resided for eighteen months (Acts 18:1-18). Here he first became aquainted with Aquila and Priscilla, and soon after his departure Apollos came to it from Ephesus. After an interval he visited it a second time, and remained for three months (Acts 20:3). During this second visit his Epistle to the Romans was written (probably A.D. 55). Although there were many Jewish converts at Corinth, yet the Gentile element prevailed in the church there.

Some have argued from (2Cor 12:14; 13:1), that Paul visited Corinth a third time (i.e., that on some unrecorded occasion he visited the city between what are usually called the first and second visits). But the passages referred to only indicate Paul's intention to visit Corinth [comp. (1Cor 16:5), where the Greek present tense denotes an intention], an intention which was in some way frustrated. We can hardly suppose that such a visit could have been made by the apostle without more distinct reference to it.

EBD - Easton's Bible Dictionary