The Persian Empire grew in the vacuum left by Assyria's destruction of the Kingdom of Elam. Prince Teispes captured Anshan, once a stonghold of the Elamites and began to call himself "King of the City of Anshan". His father, Achaemenes 681 BC, a warrior chief, is apparently responsible for training and organising the early Persian army and it is his name that begins the royal line of Achaemenian Kings.

Teispes expanded the Kingdom of Parsa and on his death divided it into two parts. Giving the northern region to his son Ariaramenes and the southern region to his son Cyrus. Ariaramenes took the title "Kings of Kings" , Cyrus referring to himself as "King of Parsumash". It is Cyrus however for reasons unknown, that rules a united Persia. Through the marriage of Cyrus' son Cambyses to the Median Princess Mandane, the royal families of Media and Persia are united. From this union a son is born called Kurush, whom we know as "Cyrus the Great."

Cyrus becomes the ruler of all Persia in 559 B.C. In 550 B.C the Median King, Astyages marches against Cyrus. The two armies meeting on the plain of Murghab. The Medians revolted after some skirmishing and handed their King and their capital over to Cyrus, who spares their capital Ecbatana and combines the army with his own.

Now the Lydian King Croesus sees an opportunity to seize land east of the river Halys. Although recently securing alliances with Egypt , Babylonia and Sparta, he does not call upon their assistance when he attacks and captures the Median fortress of Pteria in 547 B.C. Within a few months the army of Cyrus II clashes with the Lydians outside Pteria. The Lydian lancers are unable to break the Persian and Median cavalry and the battle ends without a victor. The larger Persian army holds the field and Croesus withdraws back to Sardis calling on his allies to prepare armies for the next spring. Cyrus waits until Croesus has began the demobilise his army, which was normal practice because of the severe Asia Minor winters.

Advancing quickly to catch the Lydians unprepared, Cyrus meets a hurriedly formed Lydian army on the plains outside Sardis on the Plain of Thymbra. To deal with the Lydian lancers, Cyrus uses the camels from his baggage train. With armed riders, the camels form the first line, followed by the infantry. The Lydian horses were pannicked by the unfamiliar smell of these animals. Their riders dismounting to fight the Persians. Although the cavalry were pushed back and routed, most of the army was able retreat to safety behind the walls. On the 13th day of the siege, before any help could arrive, the Persians scaled a lightly defended part of the wall and captured the city. Cyrus not only gained great wealth, but access to the Aegean and control of Ionian cities on the Western coast of Asia Minor.

Moving east, he took Parthia , Chorasmis, and Bactria. In 541 B.C he begins his campaign against Babylonia but was delayed by the river Gyndes. An unfordable river that claimed one of his sacred white horses as it tried to cross it. Greatly upset by the loss he decides to defeat the river by redirecting its flow into many smaller streams and so allows the army to cross in safety.

The Babylonian army is defeated in battle at Opis and after a short siege the Persians are led into the city by one of its governors, 539 B.C. Cyrus ensures that the religious and commercial life is not interrupted and released the Jews who had been held captive there since 589 B.C., thus earning his immortalization in the Book of Isaiah. The Persians now not only controlled the productive agricultural lands of Mesopotamia and the world's largest commercial city, but now became a great sea power with the Phoenican fleet at its disposal. When he died in 529, Cyrus' kingdom extended as far east as the Hindu Kush in present-day Afghanistan.

Cyrus' son and successor , Cambyses II, King of Babylonia, inherits some of his father's organisational and military skills but not Cyrus' popularity. He completed his fathers plan for the conquest of Egypt defeating the Saitic kingdom of Egypt and sat on the throne of the pharaohs, accepting the surrender of Libya and the Greek cities of North Africa.

Unfortunately his luck now changes, the army of 50,000 men he sends against the desert oasis colony of Greeks at Siwa in the Egyptian desert either dessert or die on route. The Phoenician sailors refuse to help with any attack on Carthage and he was forced to turn back in his campaign against the Egyptian influenced Kushite kingdom of Meroe and dies in Syria on the way home.

Following is a period of rebellion or upheaval from which Darius, the general who commanded the Immortals in Cambyses' Egyptian campaign and a member of a lateral branch of the Achaemenid family takes the throne. Darius I (also known as Darayarahush or Darius the Great ).

Darius spent the first years of his reign suppressing wide spread rebellion. After order was re-estabished, he set about organising and expanding the empire. After the Indian campaign 520 -515 B.C. which added part of north west India to the empire, Darius assembled a fleet of 200 to 300 ships and an army of 70,000 and embarked on the unsuccessful invasion of Scythia in 513 B.C. Although successful against one of the Saka nomads he was not unable to force a decisive battle with the Scythians. Lacking food and continually harashed he is forced to retreat back to the bridge of boats which the Ionian allies were guarding.

Darius retreated to Sardis while his general Megabazus proceeded to conquer most of Thrace and formed an allegiance with Alexander, king of Macedonia.

In 498 B.C. the Ionian cities of Asia Minor rebelled against Persian rule. This was initiated by the personal ambitions of some of the tyrants of the Greek cities rather than anti-Persian feelings. With the help of Athens and Eretria the Ionian forces occupied and sacked the city of Sardis, the revolt spread and other cities along the Hellespont, Caria and the Greek towns of Cyprus threw off their Persian yoke.
The Persians were quick to respond. With a combined naval and land operation, they first contained, then defeated the Ionian infantry force at Ephesus. Then Cyprus fell, and then one by one the cities were retaken. The city of Miletus, the head quarters of the rebellion, was beseiged by the Persians army and a naval force of 600 ships. A Greek fleet of 353 ships met the Persians off the island of Lade but were decisively beaten. The rebellion ended with the capture of Miletus in 494 B.C. and its population sold into slavery. With Persian authority restored over the Ionian coast, Persia installs democracies in place of the tyrants in many of the cities.

In 492 B.C. Mardonius retakes the Thracian cities lost in the rebellion and then sets sail for Athens. Darius is now out for revenge for Athens and Eretria's support of the Ionian rebellion. Unfortunately Mardonius' fleet is wrecked in a storm off Mount Athos and he is forced to return to Asia.

Under the Median admiral Datis', the Persians capture Eretria, and land at the bay of Marathon. The Battle of Marathon in 490 B.C. was only a relatively small scale affair but it had wide historical consequences.

Marathon was an infantry battle in which the weighted Greek wings quickly routed the opposing Persians wings. The Scythian allies in the Persian centre break through the Greek line, but this is too little, too late and the Persian army is routed with large casualties. The Persians loosing their myth of invincibility.

After the death of Darius I in 486 B.C., his son and successor,Xerxes, was chiefly occupied with suppressing revolts in Egypt and Babylonia. In his conquest of the Greek Peloponnesus, his vast army defeats the Spartans at Thermopylae and sacks a deserted Athens. However , with its appointed general Mardonius, the Persian army could not stand up to the combined Greek forces at Plataea. The naval defeat at Salamis and the armies destruction at Plataea stopped the western expansion of the Persian Empire and was the high tide mark of the Achaemenid empire.

By the time his successor, Artaxerxes I, died in 424, the imperial court was beset by factionalism among the lateral family branches. His son Xerxes II was murdered by Sogdianos who inturn was replaced by Darius II, another illegitimate son. Darius II 's son Artaxerxes II now was challenged by his younger brother Cyrus the Younger. Cyrus employed the Greek mercenary Xenophon, only to be defeated at Kounaxa in Babylonia.

Artaxerxes III 358 B.C. eventually pacified Anatolia and reconquered Egypt in 343 B.C.

In the same year that Darius III came to the throne 336 B.C, Alexander III became King of Macedonia.

Of all the Great Persian Kings, it is Cyrus the Great that is remembered as a great leader, a man of character and majesty.

Acheivements
The Achaemenid Persians had a concept of "One World" and the "Unification of All People". By accepting the practices and gods of the subject peoople they created the world's first religiously tolerant empire. They evolved an administrative system that was sufficiently flexible to cater for the multitude of different languages, races, religions and cultures while maintaining the fundamental unity of government necessary to maintain the empire.

The Achaemenids built an efficient infrastructure of roads and ports. They bought water to remote areas throughout the empire through the use of qanats, (underground irrigation system). Darius had a canal built to link the Nile to the Red Sea (an early precursor of the Suez Canal).

These all facilitated the exchange of commodities among the far reaches of the empire. As a result of this commercial activity, Persian words for typical items of trade became prevalent throughout the Middle East and eventually entered the English language; examples are, bazaar, shawl, sash, turquoise, tiara, orange, lemon, melon, peach, spinach, and asparagus.

Darius understood that a successful state must have on a sound economic foundation. One of his first actions was to standardise a system of measurements for weight, volume and length.

An example of the Persian 'royal cubit' was found. A black limestone ruler, exactly 18 inches in length or 33.60 cm and inscribed with the name and title of Darius. Herodotus tells us that the royal cubit was three fingers' longer than the common cubit.

Darius revolutionized the economy by placing it on a silver and gold coinage system and introduced banking houses (the word "check" comes from Old Persian).

Darius sent researchers to Egypt with the task of codification of their laws, and set up a universal legal system upon which much of later Iranian law would be based.

Sucessive Achaemenid Kings built the magnificent palace at Persepolis, where vassal states would offer their yearly tribute at the festival celebrating the spring equinox.

The Achaemenids, while borrowing on existing building technology made full use of the materials and technologies available. Using long beams of Lebanese cedar instead of stone lintels, they were able to achieve greater height with the fewer and thinner stone columns.