The original city was destroyed by the Romans about 146 B.C., but Julius Caesar had it rebuilt and established as a Roman colony just over a hundred years later (see Roman Legions and Roman Roads). Under Augustus (see Ancient Empires - Rome), it grew to become the capital of the province of Achaea.
Corinth owed much of its early success as a port to the fact that it was actually two ports - one to the Ionian and Adriatic Seas on the west side, and the other to the Aegean Sea on the east side, then separated only by the narrow isthmus.
The ancient Corinthians attempted to cut a canal through the natural barrier, but when that proved insurmountable for the "technology" of the day (i.e. crude picks and shovels), they instead constructed a slipway, called the diolkos, where boats were brought up out of the water on one side and hauled overland across to the other side. By 67 B.C., Emperor Nero made another attempt to dig a canal through the rock, but the unfinished project was abandoned after his suicide. It was not until relatively modern times, in 1893, that a canal was finally opened, as shown in photograph.
In Paul's time, Corinth had developed into a major government and commerce center of that region. It was a large cosmopolitan city, with a estimated mixed population of 400,000 people - Romans, Greeks, and Jews. Athens always led as the classic Greek city of intellectual and architectural wonders, but Corinth was where real life of the time happened. Gallio, the brother of Seneca, was proconsul around the time when Paul became very active in the region. See Paul's Second Missionary Journey and Paul's Third Missionary Journey. Also Paul In Athens.
Paul's first stay at Corinth lasted for eighteen months (Acts 18:1-18), where he first met, lived and worked with Aquila and Priscilla, who had been among the Jews ordered out of Rome by Claudius (Acts 18:2). Paul returned after a later missionary journey and remained for another three months (Acts 20:3). It was during that return visit that he wrote the Epistle to the Romans, sometime around 55 A.D.
Fact Finder: How did Paul earn his living while in Corinth?