Not forgotten, but often seen through enemy eyes
The Achaemenid Empire was never really forgotten. Greek writers recorded it in detail, the Hebrew Bible mentions its kings, and Persian rulers of later centuries recalled it in their own ways. What has been neglected is the Persian side of the story, since so many of the surviving narratives were written by Greeks. This article follows the political sequence of the dynasty, from its founding in the sixth century BCE to its defeat in 330 BCE. Dates are approximate in places, as is usual for the ancient Near East.
Cyrus and the first conquests
Cyrus II, called the Great, was a ruler of the Persians who built on the older kingdom of Anshan. Around 550 BCE he defeated the Median king Astyages and took over the Median realm, which had been a major power on the Iranian plateau. Within a few years he attacked Lydia, whose king Croesus was defeated and whose capital Sardis fell, usually dated about 547 or 546 BCE. The story of Sardis and Croesus gained a legendary colouring in Greek retelling, but the conquest itself is well attested.
In 539 BCE Cyrus turned on Babylon. According to a Babylonian chronicle, the city was taken with little fighting, and the fall of Babylon ended the Neo-Babylonian dynasty. Cyrus died in 530 BCE, reportedly on a campaign against nomadic peoples on the north-eastern frontier, though accounts differ.
Cambyses and the crisis of 522 BCE
Cyrus’s son Cambyses II conquered Egypt in 525 BCE, adding the Nile valley to the empire. He died in 522 BCE on the way home, in circumstances that are not clear. A struggle for the throne followed. In Darius’s own account, carved at Behistun, a usurper pretending to be Cambyses’ brother Bardiya seized power and was overthrown by Darius and a group of Persian nobles. Many modern historians treat this account with suspicion, since it justifies Darius’s accession, and the identity of the pretender remains debated. Rebellions broke out across the empire, and Darius spent his first years putting them down.
Darius, the Scythians and Greece
Darius I (522 to 486 BCE) consolidated the empire and expanded it, adding territory in the Indus region and across the Hellespont into Thrace. He campaigned against the Scythians north of the Black Sea, a campaign that did not achieve a decisive result.
The Greek wars began with the Ionian Revolt, in which Greek cities on the Aegean coast of Anatolia rebelled against Persian rule around 499 BCE, with some support from Athens and Eretria. The revolt was suppressed by about 493 BCE. A punitive expedition against Athens followed and was checked at Marathon in 490 BCE, the high point of the Marathon campaign 490 for the Athenians.
Xerxes and the invasion of 480 to 479 BCE
Xerxes I (486 to 465 BCE) first put down revolts in Egypt and Babylon. He then led a very large expedition against mainland Greece, using a bridge of boats over the Hellespont. The Persians fought at Thermopylae, burned Athens, and then lost the naval battle of Salamis in 480 BCE, where the Greek fleet under the leadership of Athens relied on Themistocles naval strategy to fight in confined waters. A year later, in 479 BCE, a land army of allied Greeks, including a Spartan-led hoplite phalanx, defeated the Persian forces at Plataea.
From the Persian standpoint this was a failed expedition on the western fringe of a large realm, not the end of the empire. The Persians kept Cyprus, much of the Aegean coast and large parts of Anatolia for a long time, and later intervened in Greek politics, supporting different sides through money and diplomacy.
The long middle period
After Xerxes was murdered in a court plot, the empire continued under Artaxerxes I (465 to 424 BCE), Darius II, and Artaxerxes II (404 to 358 BCE). It faced revolts in Egypt, which broke away for several decades from about 400 BCE, and the rebellion of satraps in Anatolia. Cyrus the Younger, a Persian prince, tried to seize the throne from his brother Artaxerxes II and died at the battle of Cunaxa in 401 BCE, famously with a contingent of Greek mercenaries involved.
Artaxerxes III (358 to 338 BCE) reconquered Egypt around 343 BCE. After his death the court was disrupted by assassination and succession struggles, and Darius III came to the throne in 336 BCE. The empire he inherited was large and still wealthy, which is why its collapse to Alexander seems so abrupt.
Alexander and the end
Philip II of Macedon had planned a war against Persia, and his son Alexander crossed into Anatolia in 334 BCE. He defeated Persian forces at the Granicus River in 334 BCE and at Issus in 333 BCE, then took the Phoenician coast and Egypt. In 331 BCE, at Gaugamela in northern Iraq, the two sides met in the decisive battle in the story of Alexander versus Darius. Darius reportedly fielded a large force including scythed chariots and a small number of war elephants, though ancient numbers are unreliable, and Alexander won.
Alexander occupied Babylon, Susa and Persepolis. Darius III fled east and was killed by one of his own satraps, Bessus, in 330 BCE. Bessus declared himself king for a time, but Alexander captured and executed him. The dynasty ended, and Alexander claimed the throne.
Why did it fall so fast?
Historians suggest several contributing factors rather than a single cause: the cost of repeated rebellions, weak succession after Artaxerxes III, Alexander’s military skill, and the fact that the heartlands were in Persian hands but support from regional elites could shift quickly to a winner. These are interpretations, and the sources, especially Greek ones, do not allow certainty. The empire’s structures outlasted its dynasty, as Alexander and his successors reused much of its administration.