During the Greek Dark Ages, the Greeks lived in small tribal units; some of these small tribes were sedentary and agricultural and some were certainly nomadic. They had abandoned their cities between 1200 and 1100 BC for reasons that remain shrouded in mystery; the Greeks believed that a cataclysmic and ferocious invasion of northern Greek barbarians, the Dorians, had wiped out the Mycenean civilization. In reality, the decline and abandonment of urbanization in Greece was probably due to a combination of economic collapse and pressure from northern migrations. Greek life during the "Dark…