THE CHURCH IN CORINTH.

The letters of the apostle Paul to the Corinthians were written to the Church that resided in Corinth. The site of the city was on the Isthmus that connects the Peloponnesus to the rest of Greece. While an unavoidable passage for the land-born, North-South trade, the city's location also made East-West trade common because ships traveled from the Adriatic Sea to the Aegean Sea would cut through the Isthmus to save hundred of miles of dangerous sea travel. The method of crossing the Isthmus involved putting the ships on rollers and transporting them across the 4-mile stretch of earth that connect the 2 land masses (a canal was not constructed until the late 19th century). Corinth was both a political and commercial capital-city, and very well-trafficked with travelers; and so the population at the time of the apostle Paul was about 600,000 people and quite diverse. Some of the outcomes of this diversity were the prosperity of both: religious syncretism and immorality. Corinth had a reputation for its depravity, and the temple prostitutes of Aphrodite did not help in saving the city's bad name. There was even a Greek word reflecting the life in the city "Korinthia ' Zomai" (Corinthianize), which meant "to practice fornication."
The account of Paul's 1st visit to Corinth is recorded in Acts 18. He had found himself in Corinth after passing through Athens. When Paul came to the city he found a Jewish couple, Aquila and Priscilla, who were there because Claudius had expelled all Jews from Rome. They, like Paul, were tentmakers by trade, and so Paul stayed and worked with them. He visited the local synagogue every Sabbath. Silas and Timothy met up with Paul after their extended stay in Macedonia. They brought support from the Macedonians so that Paul could be preaching the "Word." Paul's ministry to the majority of the Jews ended up being unsuccessful (they opposed and reviled him), therefore he decided to go to the Gentiles (Non Jews). After this, many Corinthians believed including Crispus, the ruler of the synagogue. Then one night the LORD instructed Paul to continue with HIS MESSAGE and not be silent for he has many people in this city. So Paul's stay was extended.
After some time some rebel Jews attacked Paul bringing him before the tribunal, accusing him of persuading people to WORSHIP GOD in a manner that was contrary to the Law. Yet the proconsul, Gallio, found it to be a petty accusation and exonerated Paul on the basis of it being a matter of Jewish doctrine and not public affairs. Some time after that, Paul departed Corinth after a year and a half of ministry there. He went to Jerusalem, and later ended up staying in Ephesus for 3 years.
At sometime-before or while he was in Ephesus, Paul wrote a letter to the Corinthians that preceded 1 Corinthians, but it is lost. The next written letter, 1 Corinthians is a response to a letter that Paul got from the Corinthian Church, which they wrote as a response this previous letter.
Paul writes in 1 Cor. 5:9, "I wrote to you in my letter not to associate with sexually immoral people." From Chloe's household, Paul received more reports of division (1Cor 1:11), not to mention other reports of sexual immorality (5:11) and further reports of division (11:18). With all these in mind Paul wrote 1 Corinthians in response to the reports covering the topics about division, sexual immorality, lawsuits, marriage, Christian liberty, order of worship, and the resurrection.
Paul then deployed Timothy to the Church of Corinth in order to scout the situation and be a representative of Paul's teaching (4:17; 16:10-11). Timothy's visit gave Paul an urgency to change his plans and so made a 2nd visit to Corinth. This visit is commonly called the "painful visit" as Paul himself refers to it (2Cor.2:1). Form Ephesus he sailed across the Aegean Sea to Corinth for a short and hasty trip. The outcome was not as Paul had wanted. He was provoked to writhe a 3rd letter, giving the letter to Titus to deliver it to Corinth. Paul's reasoning for it is found in 2Cor.2:3-4. He also wrote in order to test them because he wanted to find out whether or not they would be obedient in all things (2Cor2:9). So the "severe letter accomplished that which Paul had desired (2Cor7:8-9).
Being encouraged, Paul wrote a 4th letter to the Corinthian Church. Known as 2 Corinthians, Paul defends his apostolic authority, encourage the church to be unified with him, gives instructions about giving, and tells of his future plans. He mentions that Titus and others are going to make a visit (2Cor8 :16-18). Paul also makes sure to note that he, himself, is going to make his 3rd visit to Corinth (12:14; 13: 1-10).
After staying in Macedonia Paul visited Greece for 3 months, making his 3rd visit to Corinth (Acts 20: 1, 2). Then Paul went back up to Macedonia and off to further ministry elsewhere (Acts 20).
In total, Paul wrote 4 letters to the Corinthians and visited them 3 times.