Seven churches of the Book of Revelation

In the Book of Revelation, the angel sent to John the Evangelist tells him (Revelation 1:11, KJV):

What thou seest, write in a book, and send it unto the seven churches which are in Asia; unto Ephesus, and unto Smyrna, and unto Pergamos, and unto Thyatira, and unto Sardis, and unto Philadelphia, and unto Laodicea[?].

These were seven of the early Christian churches in Asia Minor.

This is a stub article -- there is lots more to say here, from both a Bible scholarship and historical angle.