The decade of anarchy that intervened between the expulsion of Demetrios Poliorketes and the accession of his son Antigonos was vitally important for the koina of mainland Greece and the Peloponnese, for it had given them the incentive and the opportunity to regroup, expand, and refine the cooperative institutions by which they had in the classical period created their regional states.
Gonatas’s recognition as king of the Macedonians in 277 was not enough to turn back this tide.60 Around 275 a wave of rebellion motivated by a desire for independence rose over Achaia. Aigion, an important member of the fourth-century koinon and the seat of the regionally significant sanctuary of Zeus Homarios, expelled its Macedonian garrison and joined the western Achaian poleis in becoming part of the new koinon.61 Further to the east, Boura was sufficiently encouraged by this rising to assassinate its tyrant, and then the tyrant of neighboring Keryneia abdicated, sensing what was in store for him.62 Polybios does not mention the status of the other three Achaian cities during this period, but inland Leontion and the large eastern coastal poleis of Aigeira and Pellene probably also joined at this time, returning the koinon to its fourth-century size, lacking only Helike and Boura, destroyed in 373.63 Polybios (2.43.1) implies that until 251, membership of the Achaian koinon did not increase again; whether he should be taken literally, on the assumption that he explicitly listed all members, or not is unclear. In the intervening years there is evidence for concerted action on the part of the Achaians, directed consistently toward the goal of total independence from Macedonian control. They welcomed Pyrrhos, coming in 272 ostensibly to undermine Antigonid influence in the Peloponnese, and in 268 they joined the alliance of Greek states being formed against Antigonos, which led directly to the seven-year conflict known as the Chremonidean War.64 The exact course of the war cannot be reconstructed with any detail, but Corinth was a major bone of contention and remained in Antigonid hands, making it a focal point in the Achaians’ coordinated struggle for regional independence.65
Meanwhile, the persistent opposition of the Aitolians, who appear not to have taken part in the Chremonidean War, effected a remarkable, if ephemeral, change in their relationship with their Akarnanian neighbors, with whom they had a long history of antagonism. An inscription from Thermon (T57) records a treaty and alliance between the Aitolians and Akarnanians, of which no written source provides so much as a hint. The general paucity of evidence for Aitolian activities in this period, aside from the tangled and chronologically challenging evidence of the amphiktyonic decrees and other inscriptions from Delphi, makes this treaty difficult to place in context, but Günther Klaffenbach was probably right to place it at the end of the Chremonidean War and to explain it as a product of the attempt by Alexander of Epeiros, the son of Pyrrhos, to secure local support as a means of regaining his throne from Antigonos.66 The treaty was evidently predicated upon a successful and mutually acceptable demarcation of the territories of the two koina, fixing the Achelöos River as the boundary; this meant that the Aitolians would surrender their claims to Oiniadai and Stratos, made by force in 314, but they were allowed to keep Agrinion.67 What is truly striking about the agreement, however, is the series of rights that in effect blurred those geographical boundaries: they extend to one another the rights of intermarriage (epigamia) and property ownership (enktēsis), as well as full citizenship, available to any individual who chose to domicile himself in the other region. It is an isopoliteia decree in all but name. The first two are rights that we have seen extended to all members of the expanding koinon of the Chalkideis in the early fourth century, and that, as I shall argue below, were widespread among other koina. They provide us with an important clue to the motivations behind the construction of cooperative political institutions beyond the polis, and their presence in the Aitolian-Akarnanian treaty suggests that the commitment to the idea of regional states not only was deep and widespread but was now beginning to transcend notions of the ethnic fixity of political boundaries to a degree that was previously almost unthinkable. This treaty may give us some indication of the terms upon which other non-Aitolian communities became members of the Aitolian koinon after 279, when our only evidence for the phenomenon consists of the shifting composition of the amphiktyonic council reflected in its now fragmentary and incomplete series of decrees. Throughout the 250s and 240s, the Aitolians pursued this logic of inclusion—or influence by potential inclusion—by granting both isopoliteia and asylia to several communities in western and mainland Greece.68
Whether out of an explicit awareness of what the Aitolians were doing in this period or not, the Achaians likewise began to extend beyond the ethnic boundaries of their koinon, as they had done in the 380s with the annexation of Kalydon and Naupaktos across the Corinthian Gulf. The immediate catalyst for this expansion was in both cases opposition to Macedonian control. But we shall see later that the expansion of koinon territories may also have had significant economic effects, which must be considered alongside the more traditional security concerns cited in narratives of third-century expansion.69 In the ongoing struggle to dislodge the Macedonian-supported tyrants from the cities of the Peloponnese, the young and ambitious Aratos of Sikyon, the son of a former pro-Macedonian ruler of the city whose family had ties to Antigonos, seized control of his native city with the help of a private band of armed men.70 Since the murder of Aratos’s father, Kleinias, Sikyon had endured a series of tyrants and, along with them, significant sociopolitical upheavals that resulted in the exile of many citizens; hundreds poured back into the city upon learning of its liberation by Aratos and attempted to reclaim their property.71 In response to the internal problems created by the return of some six hundred exiles as well as to the threat of external predation, particularly by Antigonos, Aratos orchestrated the integration of Dorian Sikyon into the Achaian koinon in 251.72 Around the same time Megalopolis, the only node of Antigonid control near Sparta, ousted its own tyrant, constituting a further blow to Macedonian power in the Peloponnese.73 Aratos energetically assumed the cause of the expansion of Achaian power. In 249 a new governor was appointed to man the Antigonid garrison at Corinth, and Aratos, sensing the weakness of a new appointee, launched an attack on Corinth.74 Although it was unsuccessful, it made clear the commitment of the newly expanded Achaian koinon to a policy of independence.
The first half of the third century in mainland Greece was characterized by the reemergence and strengthening of the cooperative political institutions that developed in the fourth century and by a complete rupture of the idea that a regional polity had to be restricted to members of a single ethnic identity. And while these developments are clearly associated with resistance to Macedonian rule, they cannot be understood purely as a function of that political stance.
SHIFTING ALLIANCES, 245–229
Over the next sixteen years the Achaian koinon under the leadership of Aratos of Sikyon continued to pursue a vigorously anti-Antigonid politics and to welcome new communities into its ranks, while Aitolian ambitions set the two confederacies at odds until they joined forces for over a decade to battle Antigonid power. The Boiotian koinon, comparatively limited in its growth potential by the vigor of its western and southern neighbors as well as by the security of Macedonian control over nearby Athens, was more often than not caught in the middle of larger military and political contests. But its rich epigraphic record belies this impression of unimportance, at least to the history of political cooperation. This was, finally, the last period in which the koina of mainland Greece operated entirely free of the shadow of Rome, the arrival of which radically changed the dynamics of cooperation.
In 245 the Achaians under the leadership of Aratos of Sikyon adopted a policy of hostility toward the Aitolians, and in preparation for war they made an alliance with the Boiotians. The allies invaded Aitolia and Ozolian Lokris, now a part of the Aitolian koinon, but the Aitolians retaliated by invading Boiotia and destroying the Boiotian army at the old battle site of Chaironeia.75 The Achaians arrived too late to help, and the Boiotians now joined the Aitolian koinon.76 Refocusing, after this defeat, on Achaian expansion in the Peloponnese, Aratos seized Corinth in 243 and immediately brought it into the koinon.77 He secured his prize by crossing the isthmus and bringing Megara, the near neighbor of now pro-Aitolian Boiotia, into the koinon, and protected Corinth’s southeastern exposure
