Wikipedia
Pentapolis
A pentapolis, from the Greek words (pente), "five" and ( 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.
Usage examples of "pentapolis".
Simonides, King of Pentapolis, another monarch with another daughter of marriageable age, the contrast could not be more instructive.