The ruling dynasty of the Persians that was settled in Fārs in southwestern Iran (possibly the Parsumash of the later Assyrian records) traced its ancestry back to an eponymous ancestor, Hāxamanish, or Achaemenes. There is no historical evidence of such a king’s existence. Traditionally, three rulers fell between Achaemenes and Cyrus II: Teispes, Cyrus I, and Cambyses I. Teispes, freed of Median domination during the so-called Scythian interregnum, is thought to have expanded his kingdom and to have divided it on his death between his two sons, Cyrus I and Ariaramnes. Cyrus I may have been the king of Persia who appears in the records of Ashurbanipal swearing allegiance to Assyria after the devastation of Elam in the campaigns of 642–639 bc, though there are chronological problems involved with this equation. When Median control over the Persians was supposedly reasserted under Cyaxares, Cambyses I is thought to have been given a reunited Persia to administer as a Median vassal. His son, Cyrus II, married the daughter of Astyages and in 559 inherited his father’s position within the Median confederation.
Cyrus II certainly warranted his later title, Cyrus the Great. He must have been a remarkable personality, and certainly he was a remarkable king. He united under his authority several Persian and Iranian groups who apparently had not been under his father’s control. He then initiated diplomatic exchanges with Nabonidus of Babylon (556–539 bc), which justifiably worried Astyages. Eventually he openly rebelled against the Medes, who were beaten in battle when considerable numbers of Median troops deserted to the Persian standard. Thus in 550 the Median empire became the first Persian empire, and the Achaemenian kings appeared on the international scene with a suddenness that must have frightened many.
Cyrus immediately set out to expand his conquests. After apparently convincing the Babylonians that they had nothing to fear from Persia, he turned against the Lydians under the rule of the fabulously wealthy Croesus. Lydian appeals to Babylon were to no avail. He then took Cilicia, thus cutting the routes over which any help might have reached the Lydians. Croesus attacked, and an indecisive battle was fought in 547 bc on the Halys River. Since it was late in the campaigning season, the Lydians thought the war was over for that year, returned to their capital at Sardis, and dispersed the national levy. Cyrus, however, kept coming. He caught and besieged the Lydians in the citadel at Sardis and captured Croesus in 546. Of the Greek city-states along the western coast of Asia Minor, heretofore under Lydian control, only Miletus surrendered without a fight. The others were systematically reduced by the Persian armies led by subordinate generals. Cyrus himself was apparently busy elsewhere, possibly in the east, for little is known of his activities between the capture of Sardis and the beginning of the Babylonian campaign in 540.
Nowhere did Cyrus display his political and military genius better than in the conquest of Babylon. The campaign actually began when he lulled the Babylonians into inactivity during his war with Lydia, which, since it was carried to a successful conclusion, deprived the Babylonians of a potential ally when their turn came. Then he took full advantage of internal disaffection and discontent within Babylon. Nabonidus was not a popular king: he had paid too little attention to home affairs and had alienated the native Babylonian priesthood. The writer of Deutero-Isaiah, speaking for many of the captive Jews in Babylon, undoubtedly represented the hopes of many of Nabonidus’s subjects that Cyrus was a potential deliverer. With the stage thus set, the military campaign against Babylon came almost as an anticlimax. The fall of the greatest city in the Middle East was swift; Cyrus marched into town in the late summer of 539 bc, seized the hands of the statue of the city god Marduk as a signal of his willingness to rule as a Babylonian and not as a foreign conqueror, and was hailed by many as the legitimate successor to the throne. In one stride Cyrus carried Persian power to the borders of Egypt, for with Babylon came all that it had seized from the Assyrians and gained in the sequel.
Little is known of the remainder of Cyrus’s reign. The rapidity with which his son and successor, Cambyses II, initiated a successful campaign against Egypt suggests that preparations for such an attack were well advanced under Cyrus. But the founder of Persian power was forced to turn east late in his reign to protect that frontier against warlike tribes who were themselves in part Iranians and who threatened the plateau in the same manner as had the Medes and the Persians more than a millennium earlier. One of the recurrent themes of Iranian history is the threat of peoples from the east. How much Cyrus conquered in the east is uncertain. What is clear is that he lost his life in 529 bc, fighting somewhere in the region of the Oxus (Amu Darya) and Jaxartes (Syr Darya) rivers. The Achaemenian dynasty Cambyses
On the death of Cyrus the Great, the empire passed to his son, Cambyses II (reigned 529–522 bc). There may have been some degree of unrest throughout the empire at the time of Cyrus’s death, for Cambyses apparently felt it necessary to secretly kill his brother, Bardiya (Smerdis), in order to protect his rear while leading the campaign against Egypt in 525. The pharaoh Ahmose II of the 26th dynasty sought to shore up his defenses by hiring Greek mercenaries but was betrayed by the Greeks. Cambyses successfully managed to cross the hostile Sinai Desert, traditionally Egypt’s first and strongest line of defense, and brought the Egyptians under Psamtik III, son and successor of Ahmose, to battle at Pelusium. The Egyptians lost and retired to Memphis, which subsequently fell to the Persians. Three subsidiary campaigns were then mounted, all of which are reported as failures: one against Carthage, though the Phoenician sailors, who were the backbone of the Persian navy, declined to sail against their own colony; one against the oasis of Amon (in the Egyptian desert west of the Nile), which, according to Herodotus, was defeated by a massive sandstorm; and one led by Cambyses himself to Nubia. This latter effort was partly successful, but the army suffered badly from a lack of proper provisions on the return march. Egypt was then garrisoned at three major points: Daphnae in the east delta, Memphis, and Elephantine, where Jewish mercenaries formed the main body of troops.
The Achaemenian Empire in the 6th and 5th centuries bc.Encyclopædia Britannica, Inc.
In 522 bc news reached Cambyses of a revolt in Iran led by an impostor claiming to be Bardiya, Cambyses’ brother. Several provinces of the empire accepted the new ruler, who bribed his subjects by remitting taxes for three years. Cambyses died—possibly by his own hand but more probably from infection following an accidental sword wound—as he hastened home to regain control. Darius, a leading general in Cambyses’ army and one of the princes of the Achaemenid family, raced homeward with the troops in order to crush the rebellion in a manner profitable to himself.
Cambyses has been rather mistreated in the sources, partly because of the prejudices of Herodotus’s Egyptian informers and partly because of the propagandist motives of Darius I. Cambyses is reported to have ruled the Egyptians harshly and to have desecrated their religious ceremonies and shrines. His military campaigns out of Egypt were all reported as failures. He was accused of suicide in the face of revolt at home. It was even suggested that he was mad. There is, however, little solid contemporary evidence to support these charges. Darius I
Darius I, called the Great, tells in detail the story of the overthrow of the false Bardiya and of the first year of his own rule in his famous royal inscription cut on a rock face at the base of Mount Bīsotūn, a few miles east of modern Kermānshāh. Some historians consider Darius’s account to be mere propaganda and argue instead that Bardiya was not an imposter. According to Darius, six leading Achaemenian nobles assisted in slaying the imposter and together proclaimed Darius the rightful heir of Cambyses. Darius was a member of the Achaemenian royal house. His great-grandfather was Ariaramnes, son of Teispes, who had shared power in Persia with his brother Cyrus I. Ariaramnes’ son, Arsames, and his grandson, Hystaspes (Darius’s father), had not been kings in Persia, as unified royal power had been placed in the hands of Cambyses I by Cyaxares. Neither is named a king in Darius’s own inscriptions. Hystaspes was, however, an important royal prince and apparently the governor of Persis. Darius himself was in the mold of Cyrus the Great—a powerful personality and a dynamic ruler.