For long periods, he would entrust rule to his son and crown prince Belshazzar, whose poor performance as a politician lost him the support of the priesthood and even the military class, in spite of his capability as a soldier.

[3] To the east, the Persians' political and military power had been growing at a rapid pace under the Achaemenid dynasty, and by 540 BC, Cyrus had initiated an offensive campaign against the Neo-Babylonian Empire.

He seemed to have left the defense of the kingdom to Belshazzar (a capable soldier but poor diplomat who alienated the political elite), while occupying himself with studies like excavating foundation records of the temples to determine their dates.

Astyages' army betrayed him, and Cyrus established his rule at Ecbatana, putting an end to the Median Empire and elevating the Persians among the Iranic peoples.

Meanwhile, Nabonidus had established a camp in the desert of his colony of Arabia, near the southern frontier of his kingdom, leaving his son Belshazzar (Belsharutsur) in command of the army.

The Neo-Babylonian Empire had pursued a policy of population transfer but one of the first acts of Cyrus was to allow these exiles to return to their own homes, carrying with them the images of their gods and their sacred vessels.

Among Babylonians, feelings were still strong that none had a right to rule over western Asia until he had been consecrated to the office by Bel and his priests; and accordingly, Cyrus henceforth assumed the imperial title of "King of Babylon".

Cyrus claimed to be the legitimate successor of the ancient Babylonian kings and the avenger of Bel-Marduk and portrayed himself as the savior, chosen by Marduk to restore order and justice.

[13] Cyrus was assumed by the Marduk priesthood to be wrathful at the impiety of Nabonidus who had moved the images of the local gods from their ancestral shrines to his formal capital Babylon.

It was only when Darius I acquired the Persian throne and ruled it as a representative of the Zoroastrian religion that the old tradition was broken and the claim of Babylon to confer legitimacy on the rulers of western Asia ceased to be acknowledged.

[citation needed] Immediately after Darius seized Persia, Babylonia briefly recovered its independence under a native ruler, Nidinta-Bel, who took the name of Nebuchadnezzar III.

[14] A year later, in 521 BCE, Babylon again revolted and declared independence under the Armenian King Arakha, who took the name Nebuchadnezzar IV; on this occasion, after its capture by the Persians, the walls were partly destroyed.

It has long been maintained that the foundation of Seleucia diverted the population to the new capital of Babylonia, and that the ruins of the old city became a quarry for the builders of the new seat of government, but the recent publication of the Babylonian Chronicles of the Hellenistic Period has shown that urban life was still very much the same well into the Parthian age (150 BC to 226 AD).

Tolini proposes that a portion of the Persian army, under the command of General Ugbaru, penetrated the Enlil Gate on the West side of the Euphrates, then crossed the river to take the eastern districts of Babylon.

[26] The Cyropaedia, a partly fictional biography of Cyrus the Great which may contain a historical core,[27] contains content as described by Xenophon who had been in Persia as one of the Ten Thousand Greek soldiers who fought on the losing side in a Persian civil war, events which he recounted in his Anabasis.

(29) Gadatas and his men, seeing the gates swing wide, darted in, hard on the heels of the others who fled back again, and they chased them at the sword's point into the presence of the king.

This system of government reached its peak after the conquest of Egypt by Cambyses II during his reign, thereafter receiving its ideological foundation in the inscription of the Persian kings.

[32] Deutero-Isaiah's predictions of the imminent fall of Babylon and his glorification of Cyrus as the deliverer of Israel date his prophecies to 550–539 BCE, and probably towards the end of this period.