An Athenian light soldier
The Athenian military were the armed forces of Athens and the Delian League of Ancient Greece. Athens was predominantly a naval power following the Greco-Persian Wars, during which Themistocles took advantage of a silver strike at Oreoi to create a new fleet of triremes to fight back the Persian invasions. Athens used this navy to defeat the Persians at the Battle of Salamis in 480 BC, turning the tide of the war.
Meanwhile, Athens had also mobilized a land army to aid its Spartan allies on the battlefield. As Athens realized its imperial ambitions through the Delian League, it strengthened its military, which would soon come into conflict with Sparta in the Peloponnesian War a few decades later as both city-states attempted to assert their hegemony. The Athenian military was mostly drawn from middle to upper-class city dwellers, with Athens' wealthier citizens bringing their horses and fine armor into battle and their middling-sort soldiers bringing their standard armor, swords/spears, and shields with them and fighting on foot. Athens' poorer citizens often served as archers or javelinmen on land, but also as sailors in the Athenian navy. Athens' dominance of the seas would ensure that Athens would remain free of naval blockade during the Siege of Athens in 431-429 BC, but their hegemony was challenged by the nascent Spartan navy later in the war, as Persia provided ships and skilled oarsmen to the Spartan alliance. The Athenians wasted much of their military in the disastrous Sicilian Expedition of 415-413 BC, losing almost all of their veteran oarsmen in the process. This allowed for the Spartans and their allies to counterattack against Athens, which was starved into surrender in 404 BC. Athens' army was largely disbanded and Athens turned into a puppet state of Sparta. While Athens would maintain a degree of autonomy - and an army along with it - until the 1st century BC, its navy was no longer the feared menace it once was.