In 479 BCE a most unusual thing happened. Potidaia had been minding its own business when an army of Persians came along and, there being little other entertainment at the time, decided to besiege it.
All was going fairly well during the siege, with the Potidaians resisting and the Persians determined to wait it out, when suddenly the sea receded and the Persians were presented with an open path into the city. So, they called out ranks and progressed toward the prize, when a tsunami rushed in and took them out.
Scientists for years didn’t believe the story, but recent research has indicated that the area indeed is prone to a meteotsunami. These require a long, narrow, body of water to be successful, and it just happens that Potidaia resides at the end of one.
As can be seen from this coin, Potidaia was a colony of Corinth. In 430 BCE, the Battle of Potidaia, which was between Athens on one side and Potidaia with Corinth on the other, was one of the catalysis for the Peloponnesian War.
This coin may have been minted between 363 BCE and 356 BCE, when the city was under the control of Athens. The Athena on the obverse hints at that, though Pegasos still reminds one of their Corinthian heritage. This particular coin is unlisted and I could not find another of the type.
In 356 BCE Philip II took the city and destroyed it. The site was much later rebuilt by Kassander as his vanity city of Kassandreia.
429 BCE
Amyntas III appeals to the Spartans against the Chalkidian League. Akanthos, Argilos, and Stageira also claim that membership was forced upon them. Potidaia is separated from the League.