E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
Pentapolis. (Greek, pente polis.)
(1) The five cities of the plain: Sodom, Gomorrah, Admah, Zeboim, and Zoar, four of which were consumed with fire, and their site covered with the Lake Asphaltits, or the Dead Sea.
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(2) The five cities of Cyrenaica, in Egypt: Berenic, Arsinoe, Ptolemais, Cyren, and Apollonia.
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(3) The five cities of the Philistines Gaza, Gath, Ascalon, Ashdod, and Ekron.
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(4) The five cities of Italy in the exarchate of Ravenna: Rimini, Pesaro, Fano, Sinigaglia, and Ancona. These were given by Pepin to the Pope.
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(5) The Dorian pentapolis: Cnidos, Cos, Lindos, Ialysos, and Camiros.