After leaving Athens, Paul went to Corinth (Acts 18:1), a wealthy commercial Greek city that Julius Caesar had refounded as a Roman colony approximately a century earlier. According to Strabo (who was about 20 years old at the time Corinth was refounded and who lived some 60 years thereafter), Caesar colonized the city mainly with persons of the “freedmen class.” (Geography, 8.6.23)
Much earlier, the Corinthians, as part of the Achaean League, joined in opposing Rome. They “behaved so contemptuously toward the Romans that certain persons ventured to pour down filth upon the Roman ambassadors when passing by their houses.” When the Romans won the war, Roman consul Leucius Mummius (in 146 BCE) razed the city to the ground. (Geography, 8.6.23) The men were slain, and the women and children were sold as slaves.
As a Roman colony, Corinth flourished to a greater extent than formerly. Commenting on what contributed to the wealth of the city, Strabo stated: “Corinth is called ‘wealthy’ because of its commerce, since it is situated on the Isthmus and is master of two harbors, of which the one [Cenchreae] leads straight to Asia, and the other [Lechaeum] to Italy; and it makes easy the exchange of merchandise from both countries that are so far distant from each other. And just as in early times the Strait of Sicily was not easy to navigate, so also the high seas, and particularly the sea beyond Maleae [the southernmost tip of the Peloponnesian peninsula], were not, on account of the contrary winds; and hence the proverb, ‘But when you double Maleae, forget your home.’ At any rate, it was a welcome alternative for the merchants both from Italy and from Asia to avoid the voyage to Maleae and to land their cargoes here. And also the duties on what by land was exported from the Peloponnesus and what was imported to it fell to those who held the keys. And to later times this remained ever so. But to the Corinthians of later times still greater advantages were added, for also the Isthmian Games, which were celebrated there, were wont to draw crowds of people.” (Geography, 8.6.20)
Largely on account of the cult of the goddess Aphrodite, Corinth was a morally decadent city, and the cult itself served to create wealth. “The temple of Aphrodite,” wrote Strabo, “was so rich that it owned more than a thousand temple slaves, courtesans, whom both men and women had dedicated to the goddess. And therefore it was also on account of these women that the city was crowded with people and grew rich; for instance, the ship captains freely squandered their money, and hence the proverb, ‘Not for every man is the voyage to Corinth.’ (Geography, 8.6.20)
Paul met Aquila and Priscilla (Prisca) who had recently come to Corinth because of the decree of Claudius that ordered the Jews to leave Rome. By trade, they were tentmakers, as was he. Thereafter Paul lived and worked with them. Every Sabbath, he would go to the synagogue and use the opportunity to share with the Jews and non-Jews who assembled there the glad tidings about Jesus Christ. (Acts 18:2-4)
Later, when Silas and Timothy arrived from Macedonia and he had their assistance, Paul appears to have been able to devote even more time to proclaiming the message about the Son of God. In time, the Jews who persisted in unbelief began to oppose and revile the apostle. He then made it clear to them that he, from then onward, would give his full attention to non-Jews and thereafter began to teach in the home of a believer, Titius Justus. This residence was located next to the synagogue. During the course of Paul’s activity, the synagogue leader or official named Crispus and his entire household became believers, as did many other Corinthians. (Acts 18:5-8)
The opposition from his fellow countrymen likely caused Paul to fear that they would force him to leave Corinth, as had often happened in other cities where he had been. To allay his fears, the Lord Jesus Christ, in a night vision, reassured him that no harm would come to him and that many more people would become believers. Paul remained in the city for a year and six months. (Acts 18:9-11)
After Gallio, the older brother of Seneca the philosopher, assumed his position as proconsul of Achaia (which proconsulship began either in 51 or 52 CE), the unbelieving Jews endeavored to have him take action against Paul. They accused the apostle of trying to persuade people to worship God in a manner that was contrary to the law. When Paul tried to defend himself, Gallio refused to involve himself with the case, telling the Jews that he would judge matters involving a crime or serious villainy but not things pertaining to their law. As a result, either Jewish accusers or non-Jewish bystanders turned against Sosthenes, the leader of the synagogue, and began to beat him. Gallio, though, paid no attention to their action. (Acts 18:12-17) If the synagogue leader is the same Sosthenes mentioned in 1 Corinthians 1:1, the incident before Gallio may have brought an end to his blind opposition and caused him to think seriously about what Paul had proclaimed, resulting in his becoming a believer.
The apostle had deep love for the believers in Corinth and continued to be concerned about them after he left the city. Therefore, when news about problems among the believers reached him, he wrote the letters that have been preserved as 1 and 2 Corinthians.
See http://bibleplaces.com/corinth.htm for pictures of and additional information on Corinth.