Revelation was written to seven churches on the mainland of Asia Minor (Turkey).  The Revelation was intended to encourage believers in the midst of Roman persecution, by relating that the Lord is in control and would be the ultimate victor and to reveal eschatology, future end time events.
    

Patmos is in the route between Rome and Ephesus.  Christians were persecuted in Ephesus by the Roman emperor Domitian.  Tradition states that John was exiled to Patmos in that persecution of 95 A.D., though there seems to be no evidence of it being a penal colony.  He lived in a cave with his scribe Prochoros, now called the Cave of the Apocalypse.   Prochoros was one of the seven deacons ordained by the Apostles and later became the bishop of Nicodemia. Tradition states the John died in 104 A.D. at the age of 99 and was buried in Ephesus.  The new emperor Neva gave John permission to return to Ephesus and continue his ministry.¹  

Patmos

Patmos is 140 miles from Athens, which takes about 10 hours by ferry.  Patmos has about 3000 inhabitants, with 3 schools for about 300 children.  It is 163 miles from Piraeus.  It is volcanic and rocky with little rainfall, though it did rain two days on us, and reportedly we were there for the worst storm in 20 years on the Aegean, delaying our departure by a day.  Patmos has three villages the port village of Skala, Chora, and Kambos.  The island is about 8 miles long and 5 miles wide, and has 40 miles of shoreline.   From the 6th to the 9th century, Patmos was raided by pirates.  Then was under Turkish dominion from 1523-1912, then Italian, finally becoming a part of Greece in 1948.

Patmos view of Aegean and Church of Apocalypse*
 

The Cave of the Apocalypse lies about halfway along the road from Skala to Chora, totally enclosed by the Monastery of the Apocalypse built around it.  Pictures are not allowed.  Seven silver lamps hang from the cave, the largest above where John slept.  There are niches in the stone believed to be where John rested in his head and another for his hand, in the shallow cave. The monastery was built in the 17th century to protect and honor the cave.  The church of St. Ann (mother of Mary) was built there first in the 11th century.  Also in this monastery, is the seminary school of Patmian which started in 1713, halted by Italians in 1912 but resumed in 1947 and continues today. 

 Besides Samos, the islands of Cos, Rhodes, Leipsoi, Leros, and Icaria are nearby, and Turkey is about 40 miles away, all in the northeastern Aegean.   Patmos is the northernmost island of the Dodecanese islands lying between Icaria and Samos to the north, Leipsoi to the east, and Leros to the south. The terrain of Patmos is mountainous, volcanic and rocky. 

Patmos view of harbor from Monastery of St John*