Cyrus II, the founder of the Achaemenian Empire, united Babylonia with his country in a personal union, assuming the title of “King of Babylonia, King of the Lands.” His son Cambyses was appointed vice-king and resided in Sippar. The Persians relied on the support of the priests and the business class in the cities. In a Babylonian inscription, Cyrus relates with pride his peaceful, bloodless conquest of the city of Babylon. At the same time, he speaks of Marduk as the king of gods. His moderation and restraint were rewarded: Babylonia became the richest province of his empire. There is no indication of any national rebellion in Babylonia under Cyrus and Cambyses (529–522). That there must have been an accumulation of discontent became clear at the ascension to the throne of Darius I (522–486), when a usurper seized the throne of Babylonia under the name of Nebuchadrezzar (III) only to lose both the throne and his life after 10 weeks. Darius waived any punitive action. He had to take more drastic measures in 521, when a new Nebuchadrezzar incited another rebellion. This usurper’s reign lasted two months. Executions and plundering followed; Darius ordered that the inner walls of Babylon be demolished, and he reformed the organization of the state. Babylon, however, remained the capital of the new satrapy and also became the administrative headquarters for the satrapies of Assyria and Syria. One result was that the palace had to be enlarged.
Babylonia remained a wealthy and prosperous land, in contrast to Assyria, which was still a poor country. At the same time, the administration of the kingdom was more and more in the hands of the Persians, and the tax burdens grew heavier. This produced discontent, centring especially on the large temples in Babylon. Xerxes (486–465) had his residence in Babylon while he was crown prince, and he knew the country very well. When he assumed his kingship, he immediately curtailed the autonomy of the satrapies. This, in turn, gave rise to many rebellions. In Babylonia there were two short interim governments of Babylonian pretenders during 484–482. Xerxes retaliated by desecrating and partially destroying the holy places of the god Marduk and the Tower of Babel in the city of Babylon. Priests were executed, and the statue of Marduk was melted down.
The members of the royal family still resided in the palaces of the city of Babylon, but Aramaic became more and more the language of the official administration. One source of information for this period are the clay-tablet archives of the commercial house of Murashu and Sons of Nippur for the years of 455–403, which tell much about the important role the Iranians played in the country. The state domains were largely in their hands. They controlled many minor feudal tenants, grouped into social classes according to ancestry and occupation. The business people were predominantly Babylonians and Aramaeans, but there were also Jews.
The documents become increasingly sparse after 400. The cultural life of Babylon became concentrated in a few central cities, particularly Babylon and Uruk; Ur and Nippur were also important centres. The work of astronomers continued, as evidenced in records of observations. Nabu-rimanni, living and working around 500, and Kidinnu, 5th or 4th century bce, were known to the Greeks; both astronomers are famous for their methods of calculating the courses of the Moon and the planets. In the field of literature, religious poetic works as well as texts of omens and Sumero-Akkadian word lists were constantly copied, often with commentaries.
For additional discussion of the Achaemenians and their successors, see Iran, history of. Wolfram Th. von Soden Mesopotamia from c. 320 bce to c. 620 ce
The political history of Mesopotamia between about 320 bce and 620 ce is divided among three periods of foreign rule—the Seleucids to 141 bce, the Parthians to 224 ce, and the Sāsānians until the Arab invasions of the 7th century ce. Sources are scarce, consisting mainly of a few notices in the works of classical authors such as Strabo, Pliny, Polybius, and Ptolemy, while the cuneiform sources are mainly incantations, accounts of religious rites, and copies of ancient religious texts. The Seleucid period
At the end of the Achaemenian Empire, Mesopotamia was partitioned into the satrapy of Babylonia in the south, while the northern part of Mesopotamia was joined with Syria in another satrapy. It is not known how long this division lasted, but, by the death of Alexander the Great in 323 bce, the north was removed from Syria and made a separate satrapy.
Mesopotamia in Seleucid-Parthian times.Encyclopædia Britannica, Inc.
In the wars between the successors of Alexander, Mesopotamia suffered much from the passage and the pillaging of armies. When Alexander’s empire was divided in 321 bce, one of his generals, Seleucus (later Seleucus I Nicator), received the satrapy of Babylonia to rule. From about 315 to about 312 bce, however, Antigonus I Monophthalmus (The “One-Eyed”) took over the satrapy as ruler of all Mesopotamia, and Seleucus had to flee and accept refuge with Ptolemy of Egypt. With the aid of Ptolemy, Seleucus was able to enter Babylon in 312 bce (311 by the Babylonian reckoning) and hold it for a short time against the forces of Antigonus before marching to the east, where he consolidated his power. It is uncertain when he returned to Babylonia and reestablished his rule there; it may have been in 308, but by 305 bce he had assumed the title of king. With the defeat and death of Antigonus at the Battle of Ipsus in 301, Seleucus became the ruler of a large empire stretching from modern Afghanistan to the Mediterranean Sea. He founded a number of cities, the most important of which were Seleucia, on the Tigris, and Antioch, on the Orontes River in Syria. The latter, named after his father or his son, both of whom were called Antiochus, became the principal capital, while Seleucia became the capital of the eastern provinces. The dates of the founding of these two cities are unknown, but presumably Seleucus founded Seleucia after he became king, while Antioch was built after the defeat of Antigonus.
Mesopotamia is scarcely mentioned in the Greek sources relating to the Seleucids, because the Seleucid rulers were occupied with Greece and Anatolia and with wars with the Ptolemies of Egypt in Palestine and Syria. Even the political division of Mesopotamia is uncertain, especially since Alexander, Seleucus, and Seleucus’ son Antiochus I Soter all founded cities that were autonomous, like the Greek polis. The political division of the land into 19 or 20 small satrapies, which is found later, under the Parthians, began under the Seleucids. Geographically, however, Mesopotamia can be divided into four areas: Characene, also called Mesene, in the south; Babylonia, later called Asūristān, in the middle; northern Mesopotamia, where there was later a series of small states such as Gordyene, Osroene, Adiabene, and Garamea; and finally the desert areas of the upper Euphrates, in Sāsānian times called Arabistān. These four areas had different histories down to the Arab conquest in the 7th century, although all of them were subject first to the Seleucids and then to the Parthians and Sāsānians. At times, however, several of the areas were fully independent, in theory as well as in fact, while the relations of certain cities with provincial governments and with the central government varied. From cuneiform sources it is known that traditional religious practices and forms of government as well as other customs continued in Mesopotamia; there were only a few Greek centres, such as Seleucia and the island of Ikaros (modern Faylakah, near Kuwait), where the practices of the Greek polis held sway. Otherwise, native cities had a few Greek officials or garrisons but continued to function as they had in the past.