Development of the polis
The archaic period saw significant urbanisation and the development of the concept of the polis as it was used in Classical Greece. By Solon’s time, if not before, the word “polis” had acquired its classical meaning, and though the emergence of the polis as a political community was still in progress at this point, the polis as an urban centre was a product of the eighth century. However, the polis did not become the dominant form of socio-political organisation throughout Greece in the archaic period, and in the north and west of the country it did not become dominant until some way into the Classical period.
The urbanisation process in archaic Greece known as “synoecism” – the amalgamation of several small settlements into a single urban centre – took place in much of Greece in the eighth century BC. Both Athens and Argos, for instance, began to coalesce into single settlements around the end of that century. In some settlements, this physical unification was marked by the construction of defensive city walls, as was the case in Smyrna by the middle of the eighth century BC, and Corinth by the middle of the seventh century BC.
It seems that the evolution of the polis as a socio-political structure, rather than a simply geographical one, can be attributed to this urbanisation, as well as a significant population increase in the eighth century. These two factors created a need for a new form of political organisation, as the political systems in place at the beginning of the archaic period quickly became unworkable.
Source: Wikipedia
