The city was the capital of proconsular Asia, which was the western part of Asia Minor. It was colonized principally from Athens.
The city abounded with the most eminent orators, philosophers, etc., in the world and was adorned with the most splendid buildings. It was famous for possessing the Temple of Diana (in the New Testament Diana is a translation of the Greek word Artemis), considered one of the seven wonders of the ancient world.
The city was also known for building the largest outdoor theatre in the world, capable of containing 50,000 spectators. For many years during the Roman period it was the second largest city of the Roman Empire (the largest being the empire's capital city of Rome). In the first century B.C. it had a population of more than 250,000, making it the second largest city in the world.
The church was founded by the Apostle Paul:
"And it happened, while Apollos was at Corinth, that Paul, having passed through the upper regions, came to Ephesus. And finding some disciples he said to them, "Did you receive the Holy Spirit when you believed?" So they said to him, "We have not so much as heard whether there is a Holy Spirit." And he said to them, "Into what then were you baptized?" So they said, "Into John’s baptism."
"Then Paul said, "John indeed baptized with a baptism of repentance, saying to the people that they should believe on Him who would come after him, that is, on Christ Jesus." When they heard this, they were baptized in the name of the Lord Jesus. And when Paul had laid hands on them, the Holy Spirit came upon them, and they spoke with tongues and prophesied . . . . And he went into the synagogue and spoke boldly for three months, reasoning and persuading concerning the things of the kingdom of God." (Acts 19:1-6, 8, see also Acts 18:19-21, NKJV throughout)
Although he visited the city briefly during his second missionary journey, he returned during his third missionary journey and stayed for a little more than three years
It was during his second visit that Paul experienced the city's fanatical devotion to the pagan goddess Diana, especially from those who made their living off of her worship:
"And about that time there arose a great commotion about the Way (the way of life of a true Christian). For a certain man named Demetrius, a silversmith, who made silver shrines of Diana, brought no small profit to the craftsmen.
"He called them together with the workers of similar occupation, and said: 'Men, you know that we have our prosperity by this trade. Moreover you see and hear that not only at Ephesus, but throughout almost all Asia, this Paul has persuaded and turned away many people, saying that they are not gods which are made with hands. So not only is this trade of ours in danger of falling into disrepute, but also the temple of the great goddess Diana may be despised and her magnificence destroyed, whom all Asia and the world worship.'
"Now when they heard this, they were full of wrath and cried out, saying, 'Great is Diana of the Ephesians!
"And when the city clerk had quieted the crowd, he said " . . . what man is there who does not know that the city of the Ephesians is temple guardian of the great goddess Diana, and of the image which fell down from Zeus? Therefore, since these things cannot be denied, you ought to be quiet and do nothing rashly.' " (Acts 19:23-28, 35-36)
The church in the city is the first of seven that received a spiritual evaluation directly from God:
"These things says He who holds the seven stars in His right hand, who walks in the midst of the seven golden lampstands:
"I know your works, your labor, your patience, and that you cannot bear those who are evil. And you have tested those who say they are apostles and are not, and have found them liars; and you have persevered and have patience, and have labored for My name’s sake and have not become weary.
"Nevertheless I have this against you, that you have left your first love. Remember therefore from where you have fallen; repent and do the first works, or else I will come to you quickly and remove your lampstand from its place — unless you repent. But this you have, that you hate the deeds of the Nicolaitans, which I also hate.
"He who has an ear, let him hear what the Spirit says to the churches. To him who overcomes I will give to eat from the tree of life, which is in the midst of the Paradise of God." (Revelation 2:1-7).