During the apostle Paul's day, Ephesus, in what is now Turkey, was a famous trading city of Lydia and the capital of the Roman province in Asia Minor.
While imprisoned in Rome, Paul sent an epistle to the saints at Ephesus, a city he visited briefly on his second missionary journey (Acts 18:21), and where he stayed three years when he and Timothy went there to preach the gospel together. (Acts 20:31.)Their success as missionaries in Ephesus was accompanied by a great disturbance. Luke recorded that an uproar was instigated by Demetrius, a silversmith interested in protecting his livelihood of making idols for the temple of Artemis (Acts 19:24-29), which was located at Ephesus.
Artemis was the Greek goddess of fertility, the moon, wild animals and hunting. Her Roman equivalent was Diana. People from throughout the province of Asia went to the temple at Ephesus to worship Artemis. A large business in the city grew from making replicas of the shrine for devotees to carry to pagan rites and to take home as mementos of their visit to Ephesus.
As newly baptized Christian converts quit buying the idols, silversmiths and merchants stirred up the people, saying their "craft is in danger" and the temple's "magnificence should be destroyed." (Acts 19:27.)
"The whole city was filled with confusion: and . . . rushed with one accord into the theatre." (Acts 19:29.) The amphitheater could seat 25,000 people. (Understanding Paul, by Richard L. Anderson.)
Despite the uproar caused by the teachings of Paul and Timothy in the city, Ephesus became one of the chief fortresses of Christianity. Influences from Paul's work there spread over the whole province. (Acts 19:10.)
Ephesus was famous also for its magical arts. Many exorcists were so affected by the preaching of Paul that they turned from paganism to Christianity. As an expression of their sincerity they burned their books of magic. (Acts 19:19.)