Thus begins the Revelation John wrote.
The revelation begins with description, purpose, and addresses to the churches to whom it was written. It then progresses through a personalized letter to each of the seven churches.
The seven churches are seen in three ways. Primarily, they were actual churches in John’s day that actually existed. Second, they are representative of various states churches can be throughout the church age. Thirdly, although perhaps without direct support, they have been seen as “church ages”, or a pattern of how the church would progress through the time between the writing of this Revelation and the close of history.
Other than the last option, which is debatable, these are seen as both historical and instructive. As such, while much wisdom can be pulled from these chapters, and has been by many other able students, they are not seen to be part of any chronology, or, perhaps, even as formally foretelling events.