structural:reformatting, information:classification
Warfare

At least in the Archaic Period, the fragmentary nature of ancient Greece, with many competing city-states, increased the frequency of conflict but conversely limited the scale of warfare. Unable to maintain professional armies, the city-states relied on their own citizens to fight. This inevitably reduced the potential duration of campaigns, as citizens would need to return to their own professions (especially in the case of, for example, farmers). Campaigns would therefore often be restricted to summer. When battles occurred, they were usually set piece and intended to be decisive. Casualties were slight compared to later battles, rarely amounting to more than five percent of the losing side, but the slain often included the most prominent citizens and generals who led from the front.

The scale and scope of warfare in ancient Greece changed dramatically as a result of the Greco-Persian Wars. To fight the enormous armies of the Achaemenid Empire was effectively beyond the capabilities of a single city-state. The eventual triumph of the Greeks was achieved by alliances of city-states (the exact composition changing over time), allowing the pooling of resources and division of labor. Although alliances between city-states occurred before this time, nothing on this scale had been seen before. The rise of Athens and Sparta as pre-eminent powers during this conflict led directly to the Peloponnesian War, which saw further development of the nature of warfare, strategy and tactics. Fought between leagues of cities dominated by Athens and Sparta, the increased manpower and financial resources increased the scale and allowed the diversification of warfare. Set-piece battles during the Peloponnesian war proved indecisive and instead there was increased reliance on attritionary strategies, naval battles and blockades and sieges. These changes greatly increased the number of casualties and the disruption of Greek society.

Athens owned one of the largest war fleets in ancient Greece. It had over 200 triremes each powered by 170 oarsmen who were seated in 3 rows on each side of the ship. The city could afford such a large fleet—it had over 34,000 oarsmen—because it owned a lot of silver mines that were worked by slaves.

According to Josiah Ober, Greek city-states faced approximately a one-in-three chance of destruction during the archaic and classical period.