It seems to me we need a little background for how the churches in Asia Minor were established.
Acts 19 records the establishing of the church in Ephesus, the capital of the Roman province of Asia. Paul had been there previously (Acts 18:19) , but he left to report to the rest of the church. Paul left two strong believers there at Ephesus to continue the work, a couple, Priscilla and Aquila. Paul returned about a year later.
When he got there this time, Paul encounters a group of about 12 men whom Luke describes as "disciples" (19:1) who had "believed" (19:2).
However, as Paul talked with them, he saw that they had not even heard that there was a Holy Spirit. They were disciples of John the Baptist, but they had not even gotten all of John’s teaching right. For John had taught, "He who is coming after me is mightier than I, whose sandals I am not worthy to carry. He will baptize you with the Holy Spirit and fire."
Perhaps these men had been taught by Apollos, a Jew from Alexandria who was also a follower of John the Baptist. Apollos had been preaching to the Jews in Ephesus about the Lord, but he only knew the baptism of John (18:25). Priscilla and Aquila explained the way of Jesus to him more adequately. And from that point Apollos went out preaching that Jesus is the Christ.
As a result, Paul explained to them that the one of whom John prophesied had come, namely, Jesus. When they heard this, they believed in Christ and were baptized. Then Paul laid hands on them and the Holy Spirit came upon them. The men who received the teaching in Ephesus went into the outlying areas and established churches. The result was that "that all who dwelt in Asia heard the word of the Lord Jesus, both Jews and Greeks." (Acts 19:10).
Many churches were established during these two years. Evidence strongly suggests that the seven churches of Revelation were founded at this time.