Achaemenid Persian Army

The army of the Achaemenid Persian Empire was a large professional force, combining infantry, cavalry and naval elements drawn from the many subject peoples across the empire's vast territory, that carried Persian power from Cyrus the Great's conquest of Lydia in 546 BC and Cambyses's conquest of Egypt at the Battle of Pelusium in 525 BC through Darius I's Scythian campaign of 513 BC. The empire's Royal Road and network of satraps commanding regional levies let it mobilize and coordinate forces across enormous distances, and for major expeditions such as Artaxerxes III's invasion of Egypt in 343 BC it fielded armies described as roughly 300,000 infantry and 30,000 cavalry alongside a fleet of some 300 triremes and 500 transport ships. The Achaemenid army is best known in the West for the Greco-Persian Wars from 499 to 449 BC, in which it suppressed the Ionian Revolt and won at Thermopylae in 480 BC, but suffered defining defeats at Marathon in 490 BC, at sea at Salamis in 480 BC, and decisively on land at Plataea in 479 BC. Despite these losses in Greece, the Achaemenid military remained the dominant force across the Near East for another century and a half until its defeat by Alexander the Great's Macedonian army in the 330s BC.