Megarian Decree
The Megarian Decree was a set of economic sanctions levied upon Megara circa 432 BC by the Athenian Empire shortly before the outbreak of the Peloponnesian War. The ostensible reason for the Decree was the Megarians' supposed trespass on land sacred to Demeter and the killing of the athenian herald who was sent to their city to reproach them. In all likelihood, it was an act of revenge by the Athenians for the treacherous behaviour of the Megarians some years earlier. It was also a deliberate provocation towards Sparta on behalf of Pericles, who was the sponsor of the decree. The decree banned Megarians from harbours and marketplaces throughout the large Athenian Empire, allegedly strangling the Megarian economy. The sanctions would have also affected Megara's allies and may have been seen as a move by Athens to weaken her rivals and extend her influence. The ban strained the fragile peace between Athens and Sparta, which was allied with the strategically located Megara.
The Significance of the Decree
The extent to which the decree encouraged the outbreak of the Peloponnesian war is the subject of debate.[1] Our primary source for the war, Thucydides, puts very little emphasis upon the decree in his analysis of the cause of the war, treating it as a pretext on the part of the Spartans. According to Thucydides the true cause of the war was Sparta's fear of Athens' growing empire. He does not describe the decree in detail as he does the conflicts over Potidaea and Corcyra.
The main evidence we have for the significance of the decree is Aristophanes, an ancient playwright and satirist of the time. His play The Acharnians (II.530-7) mentions how the decree left the Megarians ‘slowly starving’ and caused them to appeal to the Spartans for aid. Another of Aristophanes' plays, Peace, also mentions how war was being brewed in Megara by the god of war. De Ste. Croix argues that a trade sanction would not significantly affect Megara as the decree applied only to Megarian citizens when it is likely that the majority of trade in all cities was completed by ‘Metics’ (foreigners or outsiders) who would be unaffected by a ban on citizens of Megara.
Oblique references to the decree in Thucydides seems to suggest its importance: the Spartans state that "war could be avoided if Athens would revoke the Megarian decree".[2] However, Thucydides also reports that the Spartans had sought a declaration of war from the Peloponnesian League during the rebellion of Samos in 440, well before the Megarian Decree was passed.