A pentapolis, from the Greek words πέντε (pente), "five" and πόλις (polis), "city(-state)" is a geographic and/or institutional grouping of five cities. Cities in the ancient world probably formed such groups for political, commercial and military reasons, as happened later with the Cinque Ports in England.
Significant historical cases 
The Pentapolis on the Adriatic was part of the Exarchate of Ravenna
, an administrative unit of the Byzantine Empire
. Red: The Pentapolis. Orange: Other cities of the Exarchate.
- in the biblical Holy Land, the word, occurring in Wisdom, x, 6, designates the region where five cities — Sodom, Gomorrah, Segor (A. V., Zoar), Admah and Zeboim — united to resist the invasion of Chedorlaomer (Genesis, xiv), and of which four were shortly after utterly destroyed.
- in Italy there was:
- first, a Pentapolis including: Ravenna, Forlì, Forlimpopoli, Classe, Caesarea
- Second, a medieval Duchy of the Pentapolis on the Adriatic coast east of Tuscany and north of the duchy of Spoleto, including the port cities (West to East) of Rimini, Pesaro, Fano, Sinigaglia and Ancona. It was part of the core of the Byzantine Exarchate of Ravenna. Later, after the fall of the Exarchate, it was transformed into the March of Ancona
- the Philistine Pentapolis: Ashkelon, Ashdod, Ekron, Gath, and Gaza
- the Doric – or Dorian Pentapolis: Kos, on the island of the same name in the Aegean Sea; Cnidus, in Caria on the west coast of Asia Minor; Lindus, Ialysus and Camirus, all three on Rhodes.
- the Pontic Pentapolis: Apollonia, Callatis, Mesembria, Odessos, and Tomis, all on the Euxeinos Pontos.
- The Western Pentapolis: five main Greek colonies that came to be in the Roman province of Libya Superior, the western part of Cyrenaica until Diocletian's Tetrarchy reform in AD 296 (now Libya). The most important was Cyrene and its port Apollonia, Ptolemais (the next capital after Cyrene's destruction by an earthquake), Barca (the later Arab provincial capital Barka), Balagrae (by Bayda) and Berenice (modern Benghazi); also known as the Pentapolis inferior ('lower P.'). This is the Pentapolis that is referenced in the official title of the Eastern Orthodox Patriarch of Alexandria and the Pope of the Coptic Orthodox Church.
- The Cinque Ports in England – the five being Hastings, New Romney, Hythe, Dover, and Sandwich.
Pentapolis of modern world 
United States of America 
- ^ "Pentapolis". Catholic Encyclopedia. New York: Robert Appleton Company. 1913.
- ^ Barron, James. "IF YOU'RE THINKING OF LIVING IN: FIVE TOWNS", The New York Times, July 10, 1983. Accessed May 20, 2008. "The basic five are Lawrence, Cedarhurst, Woodmere, Hewlett and Inwood. But the area also includes some unincorporated communities and two tiny villages, Hewlett Bay Park and Woodsburgh, that are not added to the final total."
See also 
Sources and references