Hastings' Dictionary of the Bible (1898)
PAT'MOS, a little rugged island in the AEgean Sea, 20 miles south of Samos and 24miles west of Asia Minor. Rev 1:9. It is from 15 to 25 miles in circumference, and is very rocky and barren. The coast is rock-bound, but indented with several deep bays. It has only a few large trees, among them a palm, some olives, and cypresses. The barrenness of the island made it a suitable spot for the banishment of Roman criminals. d. 95. Its rocky solitude well suited the sublime nature of the Revelation.
There is a grotto on a hill in the southern part of the island Isle of Patmos, which tradition points out as the place where John received the Revelation. Upon the summit of the mountain is a monastery built in honor of St. John, and having a library containing about two hundred and forty manuscripts. In the Middle Ages the island was called Palmosa, and now bears the name of Patmo.