Achaemenidai/History

Faction Overview	Strategic Overview	History
The Achaemenid Empire (550-330 BCE) was the ruling dynasty of Persia for 220 years, founded by Cyrus the Great in 550 BCE. During its existence, it held sway over a vast swathe of land ranging from Egypt and Thrace in the West to the very borders of India in the east. Following the defeat of its last king Darius III in battle at Gaugamela, it was subsequently conquered by the Macedonian King Alexander III "The Great", and thereafter partitioned by his surviving generals. 
=== Empire: Cyrus the Great ===
In 553 BCE, Kūruš II, petty king of Anshan, great-grandson of Teispes and later know as Cyrus the Great, led a revolt against the Medes. Through shrewd military leadership and sound sociopolitical policies, Cyrus would prevail against the odds, succesfully defending his homeland from attack, in turn overthrowing the unpopular and despotic (according to the account of Greek historian Herodotus) son of late Cyaxares and king of the Medes, Astyages. The Mede capital of Ecbatana followed soon afterward. By 550 BCE, and in one fell swoop, Cyrus had become both ruler of Persia and all of the former Median empire. This rapid change in the status quo after the fall of Assyria and the partition of its domain was to be heavily felt; for war between Cyrus and the remaining powers proved to be inevitable. The famous Croesus of the Lydian Empire in Asia Minor, and brother-in-law of Cyaxares, was the first to strike, taking the frontier city of Pteria and enslaving its inhabitants. Meanwhile, Cyrus tried to incite the Ionian Greek colonies of Western Asia Minor to revolt against Croesus. When this failed, he armed his men along the way and counterattacked the Lydians, which came to a stalemate. Croesus retired to Sardis and made use of his famed wealth to try and assemble a huge army from mercenaries and allies such as Egypt. But Cyrus struck before that could happen, and by 546 BCE, the Lydian capital at Sardis was taken, and its empire quickly absorbed into the new Medo-Persian polity.
Later came Elam and its capital of Susa, by at least 540 BCE, and soon after, the army of king Nabonidus of Babylon was crushed, and the great city taken peacefully and without resistance on October 29 of the same year. With the defeat of the Neo-Babylonian empire, all of the empires that followed Assyria's destruction had been integrated under one King of Kings: Cyrus The Great. All but one, Egypt, remained. But Cyrus had plans towards the East; and died under obscure circumstances shrouded in legend, and which vary according to the account.
Despite Cyrus' early and unexpected death, the Achaemenid Persian empire was there to stay, and was already well guided through the path of greatness; which would be continued under other famous rulers such as Darius and Xerxes , known for the influential era of the Greco-Persian Wars.
===The Greek Wars===
As the Achaemenid empire grew to encompass most of the known world, they weren't the only ones with ideas of conquering more land in their heads. 
With all of the Middle East, Asia Minor, and Egypt in their hands, the Persians continued on to pick new enemies: the Greeks.
To maintain rule over their vast empire, the Achaemenids had instituted the satrapy system through which native regions would not be directly ruled from the capital at Pasargadae, but be administered by local strongmen to quell dissent. This system was unfortunately prone to abuse, especially in the case of the Greek city-states in Anatolia: local dissatisfaction with the corrupt rule of the Ionian satrapy soon resulted in a massive revolt that roiled Ionia for mot of the 490s BCE, which was abetted by the Greek city-states of Athens and Eretria, and could not be put down at great cost.
Once the revolt was finally suppressed, the Persians retaliated against Athens, Sparta, and several other Greek cities (mostly concentrated in Achaea) for their support of the Ionian revolt, with Darius the Great leading an invasion of Greece in 492 BCE. Although the first invasion was curtailed by a storm, he invaded again in 490 BCE and captured Eretria. In September, however, his army was defeated at the Battle of Marathon, although his army of 25,000 troops faced only 10,000 Greek troops. The Persians hurriedly re-embarked and retreated, and it would not be for another ten years that the Persians invaded Greece again.
Darius' successor Xerxes I of Persia invaded Greece again in 480 BCE, and his army of 200,000 Persian troops overran an army of 7,000 Greek troops in the Battle of Thermopylae in August 480 BCE, although the courage of the defenders cost him 20,000 troops. The Persians won the Battle of Artemisium at sea the same month, but they lost the battle of Salamis in September that year, and in July 479 BCE they were defeated at the Battle of Plataea, which ended their invasion of Greece.
On 27 August 479 BC their army was also defeated at the Battle of Mycale on their own territory, and their last stronghold in Thrace, Byzantium, fell in 478 BC. This ended the Greco-Persian Wars, although the Greeks supported an Egyptian revolt in 462-454 BCE with 200 ships, helping the 300,000 Egyptians fight the 400,000 Persians, although the Persians defeated the Egyptians after initial defeats at Pampremis and Memphis. Despite these embarrassing defeats, Persia recovered while the Greeks fought each other in the Peleponnesian War and joined Athens' side in the Corinthian War, helping the Athenians wipe out a Spartan fleet at the 394 BCE Battle of Cnidus. 
===Dissension and decadence===
===The Downfall: Alexander the Great===
In 336 BC, the Persian Empire faced its biggest and last issue when the King of Macedon, Alexander the Great, made plans to conquer Persia and avenge those killed in the Greco-Persian Wars a hundred years before. The Persians had a mighty navy located off the coast of Egypt, and they refitted at the docks of Memphis, Gaza, and Tyre. Alexander planned to capture the cities on land so that their navy could not repair itself, and he also planned a land advance to the cities of Persia with large armies. By the time he would be in the Persian heartland, he would start recruiting mercenaries, as Greek and Macedonian reinforcements would take months to arrive. He first fought the Persians in the 335 BC Battle of Halicarnassus, where he defeated the army of Memnon of Rhodes. Next, he proceeded to conquer the rest of Asia Minor, which was made easier after victories against the Persian army at the Battle of Granicus and the Siege of Halicarnassus in 334 BC. In 333 BC, he conquered the rest of Asia Minor and defeated King Darius III of Persia himself at the Battle of Issus. In 332 BC he conquered both Tyre and Gaza, and he was able to take control of Egypt without much opposition. The Persian Empire was rapidly conquered by the brilliant Alexander, who never lost a battle. In 331 BC he defeated Darius in person for a second time at the Battle of Gaugamela, and Darius was killed by his own rebellious satrap Bessus. Bessus himself was executed by Alexander out of respect for his former opponent Darius, and Alexander proceeded into Persia itself. He took Babylon, Ecbatana, and the other major cities, and in 330 BC he fought his last battle against Persia at the Battle of the Persian Gates. In that battle, the Persians held a narrow pass against Alexander's army for a month, but Alexander outflanked and defeated them with help from a local shepherd. With the last Persian army gone, Alexander was able to advance on Persepolis, which fell to him. Their last holdouts in Bactria fell without much opposition, and Alexander became the emperor of Persia and Macedon, ending the Achaemenid dynasty.
Alexander, however, did not live long and neither did his new Macedonian Empire. Upon his death, this empire was partitioned by his surviving generals: although Ptolemy gained control of Egypt, and a minor officer, Diodotus, was given control of Bactria and Greek India, the lion's share - Mesopotamia and Syria- were dominated by the Macedonian general Seleucus. It would take well over a century from Alexander's death before Persia was once more free — this time, led by the Parthian Arsacid dynasts.