Cyrus (Cyrus II) succeeded his father Cambyses I as ruler in Persis/Anshan, marking the start of the reign traditionally dated c. 559–530 BCE and the rise of Achaemenid power from a regional base in Fārs.
Conflict between Cyrus and the Median kingdom began during the reign of Babylonian king Nabonidus; later summaries based on the Nabonidus Chronicle place the outbreak of hostilities in 553 BCE, preceding the Persian overthrow of Astyages.
Cyrus defeated the Median king Astyages; sources summarizing the Babylonian chronicle tradition note Median troops revolted, Astyages was captured, and Ecbatana (Agamtanu) fell—shifting imperial leadership from Median to Persian hands.
After the fall of Media, Cyrus consolidated the new Persian-led polity and extended authority across western Iran, creating the strategic platform for subsequent campaigns into Anatolia and Mesopotamia.
Cyrus campaigned against Croesus of Lydia; the culminating defeat of Croesus at Sardis (546 BCE) brought Lydia under Persian control and opened the way to Persian domination in western Anatolia.
During the Babylonian campaign, Persian forces defeated the Babylonians at Opis in early October 539 BCE, a decisive blow preceding the rapid collapse of Neo-Babylonian defenses.
Following Opis, the city of Sippar fell on 10 October 539 BCE, further isolating Babylon and accelerating the end of the Neo-Babylonian state.
Persian forces took Babylon in October 539 BCE; the Babylonian chronicle tradition describes the city’s capture with minimal resistance, marking the incorporation of Mesopotamia into Cyrus’s empire.
After the city’s capture, Cyrus formally entered Babylon on 29 October 539 BCE, consolidating Persian rule in a major imperial capital and legitimizing the new regime through local political-religious forms.
The Cyrus Cylinder, an Akkadian-language royal inscription, was created as a foundation deposit after the conquest of Babylon, presenting Cyrus’s rule as sanctioned by Marduk and emphasizing restoration of temples and displaced cult objects.
In biblical tradition, Cyrus issued a proclamation permitting exiled Judeans to return to Jerusalem and rebuild the Temple—an influential example of his wider imperial policy of local restoration and accommodation.
Cyrus died around 530 BCE during a campaign in the east; later Greek tradition commonly associated his death with fighting the Massagetae, and his death marked the transition to the reign of his son Cambyses II.
Reign of Cyrus the Great (c. 559–530 BCE)
