My bad: Phillip also came close to unifying the Greeks.

A union after the fashion of a modern nation-state would have been both practically impossible and desired by no one. Each Greek state was fiercely defensive of its autonomy. From the Persian Wars onwards, the Greeks increasingly regarded this autonomy as a central feature of their collective identity, which they referred to with the slogan ‘freedom of the Greeks’ (eleutheria tôn Hellenôn). Unification would invariably have come at the expense of some of this freedom. When Greeks theorised about joining together, they only ever conceived of this as the rise to supremacy of a single dominant state, or as a temporary alliance of theoretical equals with a specific goal. No one ever suggested, or even imagined, a single united state or government of the Greeks.

Most often, the creation of a single political power out of several Greek communities was the result of subjection by military force. There are only a few instances where some of these communities banded together voluntarily, and these never included more than a few dozen states at most (out of an estimated total of well over 1,000).

Examples of subjection as a way to bring Greek states under a single banner are common enough. Regional hegemonies include Thebes' domination of the Boiotian League, the rivalry between Pherai and Larissa over control of Thessaly, and the ongoing efforts of tyrants of Gela and Syracuse to rule all of Sicily. More famous is the subjection of the whole Peloponnese to Sparta through a network of unequal alliances that required states from Elis to Corinth to "have the same friends and enemies and to follow wherever the Spartans lead," as the oath went. Apart from the political and military demands that came with subjected status, being part of such a hegemonic alliance often included accepting whatever regime or form of government the overlord favoured. Needless to say, such arrangements were rarely popular and often unstable.

The first known Greek state to subject others to regular tribute payments (something that had previously been a feature only of Lydian and Persian overlords) was Classical Athens. While the Athenian Empire began as a voluntary alliance, it became apparent after several rebellions were violently suppressed that no state that had signed up to join would ever be allowed to leave. This behaviour caused Athens to be called a ‘tyrant city’ and allowed the Spartans to pose as liberators during the Peloponnesian War (431-404 BC). Even so, the Spartans saw the benefit of arranging their hegemony along Athenian lines, and followed up their victory with the establishment of their own tribute-levying empire, which came close to covering all of mainland Greece and the Aegean.

The conquest of Greece by Philip and Alexander follows this pattern. These kings never tried to unite Greece under a single government; rather, they forced every single state to submit to their command with regard to foreign policy, tribute and military service. The Greek states never considered this to be a dissolution of their communities into a larger whole. Rather, they always clung to hopes of restoring the ‘freedom of the Greeks’, and rebelled against their Macedonian overlords at every opportunity. Alexander faced two major rebellions against his rule, the first of which ended in the annihilation of Thebes (335 BC) and the second in the death of king Agis III of Sparta at the battle of Megalopolis (331 BC). When news reached Greece that Alexander was dead, the Greek states immediately revolted en masse, triggering the Lamian War (323-322 BC). Alexander’s successors realised that the Greek states were valuable allies, and constantly curried favour with them by promises of restoring the ‘freedom of the Greeks’ if only they would choose their side in their ongoing dynastic wars.

So much for conquest as a way to unify the Greeks. Less prominent but more positive was the phenomenon of states voluntarily cooperating and forming ruling bodies above the polis level. The earliest of these is probably the Amphicthyonic League, a group of states led by Phokis sworn to protect the neutrality of the sanctuary at Delphi. This was effectively only a defensive alliance that was activated when some power tried to seize the sanctuary or use its stockpiled dedications as a source of funds. A more substantial early example is the Panionic League or Ionian League, an alliance of cities in Western Asia Minor that celebrated festivals and planned its defence against Persia together. However, this league stopped short of establishing a common treasury, and its revolt against Persia in 499-494 BC ultimately failed because of internal divisions. Despite a similar lack of formal institutions and similar internal divisions, the alliance of 32 Greek states against Xerxes did succeed in defeating the foreign threat in 479 BC - and the alliance was effectively dissolved the following year.

In the Classical period, several regions of the Greek world realised that they would only be able to resist encroachment by powers like Athens and Sparta if they united for their defence. Sometimes groups of communities would be resettled together wholesale, much in the way that the greater states themselves had been established in the Archaic period. The most lasting of these synoikismoi was Rhodes, which was born out of the unification of four poleis about 408 BC; but the most worrying for the balance of power in Greece was the short-lived merger of Argos and Corinth during the Corinthian War of 395-386 BC.

More common, however, was the practice of establishing federations, which became increasingly common by the 4th century BC. Regions essentially reorganised their foreign policy and defence through a common council which drew on a common recruitment pool and tax base. Individual states retained their local independence, but put their defence in the hands of larger organisations in which they had a share and a vote. Some federations took remarkable strides in unifying their territory; the Arkadian federation, founded in 370 BC on the ashes of Sparta’s hegemony in the Peloponnese, established a standing army and even a common Assembly of all Arkadian citizens. In the Hellenistic period, only large federations like the Aitolian and Achaian Leagues were able to hold their own in a Mediterranean geopolitics that had far outgrown the citizen-state.

The most successful of the fourth-century Greek power blocs and the most obstinate enemy of Philip was the unequal alliance system we refer to as the Second Athenian League. This was explicitly not an Empire of the earlier stamp; it was drawn up as a voluntary alliance in which all members had an equal vote. The fact that it meant, in practice, the paying of regular tribute to serve Athenian interests, proved its undoing – but at first it was regarded as a mutually beneficial pact that allowed minor states across the Aegean and beyond to protect themselves against expansion by others. It was formed to resist Sparta, and successfully destroyed Sparta’s final bid for rule of the sea in 376-375 BC. It also protected the Greeks of the Aegean to some extent against a resurgent Persia. It always maintained the outward appearance of a council of equals deliberating on the best foreign policy, and officially repudiated Athens’ earlier attempts to extend its power over its allies to areas such as coinage and jurisdiction. The Athenians had learned that showing contempt for the ‘freedom of the Greeks’ did nothing but foster resentment and cause inevitable revolt. While the Social War of 357-355 BC reduced the Second Athenian League significantly, it was not until Philip’s victory in 338 BC that this alliance was finally dissolved.

The nature of all these forms of organisation above polis level shows, however, exactly why there was never a politically united Greece in Antiquity until the Roman conquest. In the end, federations and alliance systems were formed and maintained specifically to prevent the subjection of independent states to dominant powers and outside influence. Effective local cooperation allowed Greek states to defend their freedom, instead of pushing them gradually towards a Greek super-state.