The city of Ephesus was a major seaport in the first century Roman empire, located on the Cayster River. The river brought down much silt, forming a fertile plain, which also contributed to the wealth of the city. (Ironically, this same silt eventually filled the harbor and the coast is now three miles west of the city.) However, at the time of Paul's arrival in Ephesus it was a thriving metropolis with a long (and checkered) history. That Paul found any converts in Ephesus is itself a miracle considering both the wealth and the pagan religion that Ephesus was steeped in.
Besides its position as a land and sea trading center (being the terminus of one land route and easily accessed by two others, in addition to its favorable port) Ephesus had a unique history with Rome. "Partial recovery came to the western edges of the province only after Pompey's victory over the pirates at Korakesion off Kilikia in 67 BC cleared the eastern Aegean of that particular menace [pirates of the eastern Mediterranean]" (Rogers 7). Thus, while Ephesus' early history involved being severely punished for perceived abuses of Roman citizens and religion, its prosperity at the time Paul entered it was because of Roman actions on its behalf. Additionally, when Ceasar visited the city in the late summer of 48 BC he "remitted one-third of the tax Asia had previously paid" and revised the method of collecting taxes to make it harder to abuse (Rogers 7).
Religion was crucial to the economic life of Ephesus, as the incident described in Acts 19:23-41 illustrates. The story is ironic because while Demetrius works the crowds to chant "Great is Diana of the Ephesians" (Acts 19:28) he tells his coworkers in the idolatry business that the real problem is money (Acts 19:27). If the temple were "despised" then people would not visit it, nor purchase sacrifices there, nor patronize other shops in the city while visiting. The cities of the Roman Empire strenuously co...