For nearly two hundred years, much of Asia was under the rule of the Seleucid dynasty. Despite the family's origins tracing back to Macedonia and its members presenting themselves as Macedonian kings par excellence, the sheer diversity of their subjects meant they needed to contend with the many non-Greek cultures that they now ruled over. The greatest body of evidence for the Seleucids accommodating to local traditions can be found in Mesopotamia, more specifically in Babylon. Though it had been centuries since the last native ruler, Babylon and its elite would hold great sway in the imperial ideology of their new Seleucid masters. Babylon is where the founder Seleucus I Nicator first took power, and Mesopotamia remained a heartland of the empire until it was captured by the Parthians in the late second century BC.

From the earliest days of the dynasty's history, Babylonia was integral to the rise of the Seleucids. Alexander the Great had designated it as the capital of his newly conquered empire down to his untimely death in 323, and the city is where the standing regent Perdiccas ran operations until his own murder just a few years later in 321. As a reward for taking part in the assassination, Seleucus was granted governorship of Babylonia. His position was soon threatened by the ambitious Antigonus Monopthalmus, forcing Seleucus and his family to flee to the court of Ptolemy I in Egypt in 315. He was eventually able to return in the spring of 311, but faced off against Antigonid forces who besieged the city and ravaged the countryside for two years. Once the "Babylonian War" was brought to an end, Seleucus would take the title of king in 306, and Mesopotamia was to serve as the foundation of his burgeoning empire. The area was badly affected during the fighting, but Babylonia was exempt from any further devastation as later wars were contained to the eastern Mediterranean. In time it would prosper once again, now under the patronage of Seleucus and his son Antiochus I Soter (r. 281-261), and it is during Antiochus' reign that we find our earliest and strongest evidence of Seleucid-Babylonian accommodation.

In the excavations of Borsippa, located 18 km southwest of Babylon, a barrel-shaped piece of clay with Akkadian cuneiform was discovered under the Temple of Ezida, devoted to the Mesopotamian god Nabû. It bears a striking similarity to the famous "Cyrus Cylinder", a deposit made in the Temple of Esagila under the authority of Cyrus the Great of Persia in 539 BC. While often misleadingly described as the "first bill of human rights", its main purpose is to broadcast the legitimacy of Cyrus as the new ruler of Babylon. The cylinder of Ezida was placed during the reign of Antiochus I in 268 to celebrate the rebuilding of the temple, which was likely damaged during the Babylonian War, and operates under very similar principles:

I am Antiochus, the great king, the legitimate king, the king of the world, king of Babylon, king of all countries, the caretaker of the temples Esagila and Ezida, the first son of King Seleucus, the Macedonian, king of Babylon

When I conceived the idea of (re)constructing Esagila and Ezida, I formed with my august hands (when I was still) in the country Hatti [Syria] the (first) brick for Esagila and Ezida with the finest oil and brought (it with me) for the laying of the foundation of Esagila and Ezida.

Other tablets record Antiochus' activities in Babylon, such as his sacrifice to the moon god Sin and the rebuilding of the temple of Esagila, where he ended up using teams of elephants to clear much of the ruins and debris. While providing a sacrifice at Esagila, the king is said to have tripped and tumbled to the ground, a bad omen by any estimation. It seems not to have affected him much, and he performed "a Greek sacrifice" to counteract any negative energy this may have incurred. Through his maintenance and patronage of the temples, Antiochus is fulfilling his duties as the legitimate king of Babylon, and the titles employed in the cylinder ("king of the world", "great king" etc.) are directly taken from earlier Babylonian, Persian, and Assyrian models. Queen Stratonice I also receives special honors on the cylinder: her titles in Akkadian are normally reserved for goddesses, and her name is translated into A?tartanikku ("Astarte-fornicating").

This policy of accommodation and respect of the local traditions would have served Antiochus well as he sought to consolidate his father's empire, and it might also be reflected in his personal staff. Bêl-re'u?unu, better known by his Greek name Berossus, was a Babylonian official serving in in the court of Seleucus and Antiochus I. He is most famous as the author of the "Babyloniaca", a history of Babylonia written in Greek that is now lost, but partially survives in fragments and quotations.[9] While the style is evocative of authors like Herodotus, it catalogued the mythology and traditions of Mesopotamia. Berossus may have been compelled to write it in order to legitimize Babylonian culture for a Greek audience, or to act as a handbook for Antiochus, to whom the book is dedicated. Antiochus was born and raised in Babylon, having never laid eyes on Macedonia, and so we might not need to view his apparent affinity for local traditions as a matter of pragmatism. The line in the Antiochus Cylinder referring to his father as "King Seleucus, the Macedonian" is unusual, since it can either be interpreted as Antiochus stressing his own Greco-Macedonian ancestry or an attempt to distinguish himself as a king reared in the Babylonian model.

https://www.hellenistichistory.com/2023/09/11/hellenistic-babylon-and-s eleucid-imperial-ideology/