Megarian Decree
The Megarian Decree was a set of economic sanctions levied upon Megara c. 432 BC by the Athenian Empire shortly before the outbreak of the Peloponnesian War. This move is considered one of the first uses of economics as a foreign policy tool. The decree addressed the Megarians' supposed trespass on land sacred to Demeter known as the Hiera Orgas, the killing of the Athenian herald who was sent to their city to reproach them, and giving shelter to slaves who had fled from Athens. The Megarian decree effectively blocked Megara from trading in any port within the Delian League, isolating the city and greatly damaging its economy. The exact influence the Megarian Decree had on the beginning of the Peloponnesian War is a matter that is highly debated to this day.