1: Paul visited it 43 yrs previous to this. Paul preached to the whole providence and had heard the word. (Acts 19:10)
2: Ephesus was a major city of Asia Minor, a sea port location. It was location of the great temple of Artemis. (Acts 19:24, 27-28 34-35) This was one of the seven wonders of the world.
3: Church at Ephesus was started by Aquilla and Percilla.