The letters to the Seven Churches was given by Jesus Christ to the apostle John to be included in the Revelation of Jesus Christ which John wrote at the time of his exile to the Isle of Patmos.  The churches are at Ephesus, Smyrna, Thyatira, Pergamos, Sardis, Philadelphia, and Laodicea.  Most of the letters contained warnings that would also apply to latter day churches as well.  Only two churches were commended without too much fault and that was Smyrna and Philadelphia.  I have written my own summaries of these churches including some comments about the Church Age view as some hold.  My comments on any of these or any bible studies I do are never to be taken above the word of God or even equal to it.  They are my own comments which a reader might agree or disagree with.  The word of God is infallible, I am not.  I write only to encourage readers to study and read the word of God for themselves and share my thoughts as I read and study also.  Here are four explanations for the seven churches. Instead of arguing about which explanation is true,
perhaps we should consider that all of them may be true. Here are the four:

1. All seven churches were literal churches existing in John's day.
2. All seven churches were typical of the different types of churches in that day and age.
3. All seven churches were typical of different churches in existence throughout the world since the time of the writing of Revelation and all seven represent the different kinds of churches existing today.
4. The seven churches represent seven church age periods. We can only guess about the time periods. Only the Lord could possibly know what the periods were for sure. If the Lord tarries His coming, the period would extend and in our thinking, we would have to keep changing the time frame. I will include a possible time frame but it is only speculation