One may ask why the Greeks suddenly began to launch these overseas projects. It seems that commercial interests, greed, and sheer curiosity were the motivating forces. An older view, according to which Archaic Greece exported its surplus population because of an uncontrollable rise in population, must be regarded as largely discredited. In the first place, the earliest well-documented colonial operations were small-scale affairs, too small to make much difference to the situation of the sending community (the “metropolis,” or mother city). That is certainly true of the colonization of Cyrene, in North Africa, from the island of Thera (Santorin); on this point, an inscription has confirmed the classic account by the 5th-century Greek historian Herodotus. In the second place, population was not uncontrollable in principle: artificial means such as infanticide were available, not to mention more-modern techniques like contraception. Considerations of this kind much reduce the evidential value of discoveries establishing, for example, that the number of graves in Attica and the Argolid (the area round Argos) increased dramatically in the later Dark Age or that there was a serious drought in 8th-century Attica (that is the admitted implication of a number of dried-up wells in the Athenian agora, or civic centre). In fact, no single explanation for the colonizing activity is plausible. Political difficulties at home might sometimes be a factor, as, for instance, at Sparta, which in the 8th century sent out a colony to Taras (Tarentum) in Italy as a way of getting rid of an unwanted half-caste group. Nor can one rule out simple craving for excitement and a desire to see the world. The lyric poetry of the energetic and high-strung poet Archilochus, a 7th-century Parian involved in the colonization of Thasos, shows the kind of lively minded individual who might be involved in the colonizing movement.
So far, the vague term community has been used for places that sent out colonies. Such vagueness is historically appropriate, because those places themselves were scarcely constituted as united entities, such as a city, or polis. For example, it is a curious fact that Corinth, which in 733 colonized Syracuse in Sicily, was itself scarcely a properly constituted polis in 733. (The formation of Corinth as a united entity is to be put in the second half of the 8th century, with precisely the colonization of Syracuse as its first collective act.) The beginnings of the polis
The name given to polis formation by the Greeks themselves was synoikismos, literally a “gathering together.” Synoikismos could take one or both of two forms—it could be a physical concentration of the population in a single city or an act of purely political unification that allowed the population to continue living in a dispersed way. The classic discussion is by Thucydides, who distinguishes between the two kinds of synoikismos more carefully than do some of his modern critics. He makes the correct point that Attica was politically synoecized at an early date but not physically synoecized until 431 bce when Pericles as part of his war policy brought the large rural population behind the city walls of Athens. A more extreme instance of a polis that was never fully synoecized in the physical sense was Sparta, which, as Thucydides elsewhere says, remained “settled by villages in the old Greek way.” It was an act of conscious arrogance, a way of claiming to be invulnerable from attack and not to need the walls that Thucydides again and again treats as the sign and guarantee of civilized polis life. The urban history of Sparta makes an interesting case history showing that Mycenaean Sparta was not so physically or psychologically secure as its Greek and Roman successors. The administrative centre of Mycenaean Sparta was probably in the Párnon Mountains at the excavated site of the Menelaion. Then Archaic and Classical Sparta moved down to the plain. Byzantine Sparta, more insecure, moved out of the plain again to perch on the site of Mistra on the opposite western mountain, Taygetos. Finally, modern Sparta is situated, once again peacefully and confidently, on its old site on the plain of the river Eurotas.
The enabling factors behind the beginnings of the Greek polis have been the subject of intense discussion. One approach connects the beginnings of the polis with the first monumental buildings, usually temples like the great early 8th-century temple of Hera on the island of Samos. The concentration of resources and effort required for such constructions presupposes the formation of self-conscious polis units and may actually have accelerated it. As stated above, however, the evidence from Lefkandi makes it hard to see the construction of such monumental buildings as a sufficient cause for the emergence of the polis, a process or event nobody has yet tried to date as early as 1000 bce.
Another related theory argues that the birth of the Greek city was signaled by the placing of rural sanctuaries at the margins of the territory that a community sought to define as its own. That theory fits admirably a number of Peloponnesian sanctuaries; for instance, the temple complex of Hera staked out a claim, on the part of relatively distant Argos, to the plain stretching between city and sanctuary, and the Corinthian sanctuary on the promontory of Perachora, also dedicated to Hera, performed the same function. Yet there are difficulties. It seems that the Isthmia sanctuary, which at first sight seems a good candidate for another Corinthian rural sanctuary, was already operational as early as 900 bce, in the Protogeometric Period, and that date is surely too early for polis formation. Nor does the theory easily account for the rural temple of the goddess Aphaea in the middle of Aegina. The sanctuary is admittedly a long way from the town of Aegina, but Aegina is an island, and there is no obvious neighbour against whom territorial claims could plausibly have been asserted. Finally, a theory that has to treat the best-known polis—namely, Athens—and Attica as in every respect exceptional is not satisfactory: there is no Athenian equivalent of the Argive Heraeum.
A third theory attacks the problem of the beginnings of the polis through burial practice. In the 8th century (it is said) formal burial became more generally available, and that “democratization” of burial is evidence for a fundamentally new attitude toward society. The theory seeks to associate the new attitude with the growth of the polis. There is, however, insufficient archaeological and historical evidence for that view (which involves an implausible hypothesis that the process postulated was discontinuous and actually reversed for a brief period at a date later than the 8th century). Moreover, it is vulnerable to the converse objection as that raised against the second theory: the evidence for the third theory is almost exclusively Attic, and so, even if it were true, it would explain Athens and only Athens.
Fourth, one may consider a theory whose unspoken premise is a kind of “geographic determinism.” Perhaps the Greek landscape itself, with its small alluvial plains often surrounded by defensible mountain systems, somehow prompted the formation of small and acrimonious poleis, endlessly going to war over boundaries. That view has its attractions, but the obvious objection is that, when Greeks went to more-open areas such as Italy, Sicily, and North Africa, they seem to have taken their animosities with them. That in turn invites speculations of a psychologically determinist sort; one has to ask, without hope of an answer, whether the Greeks were naturally particularist.
A fifth enabling factor that should be borne in mind is the influence of the colonizing movement itself. The political structure of the metropolis, or sending city, may sometimes have been inchoate. The new colony, however, threatened by hostile native neighbours, rapidly had to “get its act together” if it was to be a viable cell of Hellenism on foreign soil. That effort in turn affected the situation in the metropolis, because Greek colonies often kept close religious and social links with it. A 4th-century inscription, for instance, attests close ties between Miletus and its daughter city Olbia in the Black Sea region. Here, however, as so often in Greek history, generalization is dangerous; some mother-daughter relationships, like that between Corinth and Corcyra (Corfu), were bad virtually from the start.