In Rome, any sense of community was primarily fostered by the institutions of the clientela and the gens, the former based on the relations of dependency between the poor and the rich, and the weak and the powerful; the latter based on the solidarity between related families. The Greekpolis had hardly any organizations that could be compared with these. This seems to be a fundamental difference that has been explained, sometimes, by the assumption that the polis was rooted in a form of society in the Dark Age in which not property or birth but people’s age was the organizing principle, hence the term age class society. In such a society, all members born in the same year undergo a collective form of upbringing or training, after which they are adopted into the community; rights and obligations depend on the age of the person, and in general, authority lies with the elderly. In the early 20th century AD, various African societies still followed such a pattern. Whether it was once common in Greece, however, is hard to prove. But to a large extent, this pattern can indeed be discerned in Crete, and especially in Sparta. Thus, in Sparta all boys from the age of 7 were raised collectively—an upbringing that inflicted deliberate hardships: the famous Spartan education—and organized into age or year groups. The adult men in Sparta formed messes called sussitia consisting of small groups of men—not family members—of various ages, of which the oldest again was the leader, who had to dine together on a daily basis and also, sleeping in one tent, formed the smallest units in the army. Typically, they called themselves the homoioi or Peers. In Sparta, this social organization existed at least since the 6th century BC, although our sources describing it mostly date from later times. Presumably, the Spartan organization had deliberately strengthened the features of equality, collectivity, and frugality in the 6th or even 5th centuries BC, lending Spartan society also an air of artificiality, by which it set itself clearly apart from other poleis. However, Spartan social organization probably was rooted in age-class traditions going back to the Dark Age. That is presumably true for Crete as well, but whether other Greek poleis had comparable origins remains unknown, because the evidence is lacking. Yet, it is striking that the Greek polis, notwithstanding all divisions of wealth and prestige among its citizens, was based on a relatively strong sense of community and equality: an underlying egalitarianism that in a subsequent period would give rise to the first democracy in history.