Cyrus II of Persia, famous in history as Cyrus the Great, was also called Cyrus the Elder by the Greeks. He was the founder of the Achaemenid Empire. Under his rule the empire embraced all the previous civilized and pompous states of the ancient Near East, and eventually conquered most of the Southwest Asia and the Caucasus. His vast and wide empire, spanning from the Mediterranean Sea and Hellespont in the west to the Indus River in the east, was the largest empire the world had yet seen. For the strong foundation of a greater Persia, he wisely united the two original Iranian Tribes, the Medes and the Persians. Though better known as a great conqueror, who at one point of time controlled one of the greatest empires in the world, he is best remembered for his unprecedented tolerance and generous attitude towards those he conquered.
In 600 BC, Cyrus I was succeeded by his son, Cambyses I, who reigned until 559 BC. Cyrus the Great was a son of Cambyses I. He was born in Media or, more probably, in Persis, the modern Fārs province of Iran. Several inscriptions of Cyrus the Great and later kings referred to Cambyses I as the "Great King" and "King of Anshan". There are some passages in the ‘’Cyrus cylinder’’, where Cyrus declared himself as "Son of Cambyses, Great king, King of Anshan".
In this context, it is to be noted that, ’Cyrus cylinder’ is an ancient clay cylinder discovered in the ruins of Babylon. It is broken in several pieces and is now in possession of the British Museum. The text on the Cylinder praises Cyrus, and portrays him as a king from a line of kings. It has been also called the first declaration of universal human rights.
Apart from the Cyrus cylinder, another inscription also refers Cambyses I as "an Achaemenian", and a "mighty king", which according to the bulk of scholarly opinion was engraved under Darius and considered as a later forgery by Darius.
By his own account, which is now generally believed to be accurate, Cyrus was preceded as king by his father Cambyses I, Grandfather Cyrus I. He married Cassandane, an Achaemenian woman, who was the daughter of Pharnaspes. They had two sons, Cambyses II and Bardiya, along with three daughters, Atossa, Artystone and Roxane.
After inheriting the royal throne of the Medes, Cyrus primarily intended to consolidate his overall power over the Iranian tribes of the plateau, before trying to expand his empire to the west. After his comprehensive victory over the Medes, he founded a local government for his new kingdom and inducted both Median and Persian nobles as the civilian officials. After the sweeping conquest of Asia Minor, he led his army to the eastern frontiers. In the mean time, Hyrcania and Parthia were already annexed to the Median Kingdom. Further east, he conquered, Margiana, Arachosia, Drangiana, and Bactria. After that, he crossed the Oxus River (now known as Amu Dariya), reached the Jaxartes, and built fortified towns with the object of defending the farthest frontier of his kingdom against the nomadic tribes of the Central Asia.
Near the beginning of October 539 BC, Cyrus fought the Battle of Opis in or near the strategic riverside city of Opis on the Tigris, north of Babylon. The Babylonian army was routed, and on October 10, Sippar was seized without a battle and with little to no resistance. On October 29, Cyrus himself entered the city of Babylon and was cheered by the Jewish community of the city, who welcomed him as a liberator. He allowed more than 40,000 Jews to leave Babylon and return to the Promised Land, Palestine. This step was in accordance with his policy to bring peace for all. He won the hearts of the locals by supporting local customs and even showing respect to the local deities. With the fall of Babylon, he also got the control of Syria and Palestine, which had been conquered previously by the Babylonians. He also made his mark in history, when for the first time known to the mankind, he declared the first Charter of Human Rights. He took the title of "King of Babylon and King of the Land". Cyrus had no intention of forcing conquered people into a single mould of culture and custom, he had the wisdom to leave unchanged the institution of each kingdom that he attached to the Persian Crown.
Cyrus was a great leader of men, generous, liberal and kind-hearted. The Hellenes, whom he conquered, regarded him as 'Law-giver' and the Jews as 'the anointed of the Lord'. Cyrus was intelligent enough to learn from the conquered peoples. He not only conquered the Medes, he united them with the Persians in a kind of dual monarchy of the Medes and Persians. Apart from the ability to create a great empire, Cyrus had the guiding genius to form the Achaemenian culture and civilization.
Before his death, Cyrus founded a new capital city at Pasargade in Fars, and had established a government for his vast empire. He appointed a local governor (satrap) to represent him in each province. The responsibilities of administration, legislation, and cultural activities of each province were the responsibility of the relative Satraps. According to Xenophon, the ancient Greek philosopher, historian, soldier, and student of Socrates, Cyrus is also reputed to have devised the first postal system. His principles were adopted by the future emperors of the Achaemenian dynasty.