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. Athens Though in the early part of the Classical period the city of Athens was both culturally and politically dominant, it was not until the late sixth century BC that it became a leading power in Greece. The attempted coup by Cylon of Athens (who become tyrant of Athens) may be the earliest event in Athenian history which is clearly attested by ancient sources, dating to around 636 BCE. At this time, it seems that Athens' monarchy had already ended and the archonship had replaced it as the most important executive office in the state, though the archonship could only be held by members of the Eupatridae, the families which made up Athens' aristocracy. The earliest laws of Athens were established by Draco, in 621/0; his law on homicide was the only one to have survived to the Classical period. Draco's law code aimed to replace private revenge as the first and only response of an individual to an offence committed against them. The law code of Draco, however, failed to prevent the tensions between the rich and poor which were the impetus to Solon's reforms. In 594/3 BC, Solon was appointed "archon and mediator". Exactly what his reforms consisted of