At the beginning of the book of the Revelation of St. John, John was commanded to "write in a book what you see and send it to the seven churches". We know that these seven churches were named after cities in Asia Minor (modern-day Turkey). From the Book of Revelation itself, we have St. John's description of each Church: 

1) Ephesus (Rev. 2:1-7): having labored hard and not fainted, they separated themselves from the wicked. but are admonished for having forsaken their first love.

2) Smyrna (2:8-11): admired for their tribulation and poverty. 

3) Pergamum (2:12-17): located where 'Satan's seat' is; and needs to repent of permitting false teachers. 

4) Thyatira (2:18-29): known for their charity, whose "latter works are greater than the former", however, they tolerate the teachings of a false prophetess. 

5) Sardis (3:1-6): despite their good reputation, they are dead; cautioned to fortify itself and come back to God by repentance. 

6) Philadelphia (3:7-13): steadfast in the faith, keeping God's word and enduring. 

7) Laodicea, near Denizli (see Laodicean Church) (3:14-22): lukewarm and insipid.

However many more questions remain with regard to exactly what these churches and cities would have looked like. In this classic book, Sir William Mitchell Ramsay looks at the historical context of these letters, to give a sense of what the people and culture were like in the Graeco-Roman world of St. John's day.