Median Empire in the context of "Cyrus the Great"

Nabopolassar (Neo-Babylonian Akkadian: 𒀭𒉺𒀀𒉽, romanized: Nabû-apla-uṣur, meaning "Nabu, protect the son") was the founder and first king of the Neo-Babylonian Empire, ruling from his coronation as king of Babylon in 626 BC to his death in 605 BC. Though initially only aimed at restoring and securing the independence of Babylonia, Nabopolassar's uprising against the Neo-Assyrian Empire, which had ruled Babylonia for more than a century, eventually led to the complete destruction of the Assyrian Empire and the rise of the Neo-Babylonian Empire in its place.

Of unclear, possibly Chaldean, origin and potentially connected to a powerful political family in the southern city of Uruk, Nabopolassar revolted against the Neo-Assyrian king Sinsharishkun at an opportune moment when Babylonia was already plagued by political instability. Though the advantage shifted back and forth dramatically several times, Nabopolassar managed to decisively push the Assyrians out of Babylonia after nearly ten years of fighting. Subsequent campaigns were intended to hinder the possibility of an Assyrian campaign directed at Babylonia through securing the border, but the intervention of the eastern Median Empire under Cyaxares in Nabopolassar's favor shifted the goals and the possibilities of the war.

Media (Old Persian: 𐎶𐎠𐎭 Māda; Greek: Μηδία Mēdía; Akkadian: Mādāya) was a political entity centered in Ecbatana that existed from the 7th century BC until the mid-6th century BC and is believed to have dominated a significant portion of the Iranian plateau, preceding the powerful Achaemenid Empire. The frequent interference of the Assyrians in the Zagros region led to the process of unifying the Median tribes. By 612 BC, the Medes became strong enough to overthrow the declining Assyrian empire in alliance with the Babylonians. However, contemporary scholarship tends to be skeptical about the existence of a united Median kingdom or state, at least for most of the 7th century BCE.The Median dynasty was, according to the ancient Greek historian Herodotus, a dynasty composed of four kings who ruled for 150 years under the Median Empire. If Herodotus' story is accurate, the Medes were unified by a man named Deioces, the first of the four kings who would rule the Median Empire; a mighty empire that included large parts of Iran and eastern Anatolia.According to classical historiography, Media emerged as one major power of the ancient Near East after the collapse of Assyria. Under Cyaxares (r. 625–585 BC), the kingdom's borders were expanded to the east and west through the subjugation of neighboring peoples, such as the Persians and Armenians. Media's territorial expansion led to the formation of the first Iranian empire, which at its height would have exercised authority over an area of 2.8million square kilometers, stretching from the eastern banks of the Halys River in Anatolia to Central Asia. In this period, the Median empire was one of the great powers in the ancient Near East alongside Babylon, Lydia, and Egypt. During his reign, Astyages (r. 585–550 BC) worked to strengthen and centralize the Median state, going against the will of tribal nobility, which may have contributed to the kingdom's downfall. In 550 BC, the Median capital, Ecbatana, was conquered by the Persian king Cyrus II, marking the beginning of the Achaemenid empire.While it is generally accepted that the Medes played a significant role in the ancient Near East after the fall of Assyria, historians debate the existence of a Median empire or even a kingdom. Some scholars accept the existence of a powerful and organized empire that would have influenced the political structures of the later Achaemenid empire. Others argue that the Medes formed a loose confederation of tribes rather than a centralized state.

The post-imperial period was the final stage of ancient Assyrian history, covering the history of the Assyrian heartland from the fall of the Neo-Assyrian Empire in 609 BC to the final sack and destruction of Assur, Assyria's ancient religious capital, by the Sasanian Empire c. AD 240. There was no independent Assyrian state during this time, with Assur and other Assyrian cities instead falling under the control of the successive Median (615–549 BC), Neo-Babylonian (612–539 BC), Achaemenid (539–330 BC), Seleucid (312–c. 141 BC) and Parthian (c. 141 BC–AD 224) empires. The period was marked by the continuance of ancient Assyrian culture, traditions and religion, despite the lack of an Assyrian kingdom. The ancient Assyrian dialect of the Akkadian language went extinct however, completely replaced by Aramaic by the 5th century BC.

During the fall of Assyria in the Medo-Babylonian conquest of the Assyrian Empire 626–609 BC, northern Mesopotamia was extensively sacked and destroyed by Median and Babylonian forces. The Babylonian kings, who annexed large parts of Assyria cared little for economically or socially developing the region and as such there was a dramatic decline in population density. Many of the greatest cities of the Neo-Assyrian period, such as Nineveh, were deserted and others, such as Assur, decreased dramatically in size and population. The region only began the process of recovery under the rule of the Achaemenid Empire. After his conquest of Babylon in 539, the Achaemenid king Cyrus the Great returned the cult statue of the Assyrian national deity Ashur to Assur. The Achaemenid practice of not interfering with local cultures, and the organization of the Assyrian lands into a single province, Athura, allowed Assyrian culture to endure.