Why did the Achaemenid kings use a policy of tolerance toward conquered peoples?

The Achaemenid kings adopted a policy of tolerance toward conquered peoples primarily as a pragmatic strategy to govern the largest empire the world had yet known. By permitting subject nations to retain their own religions, customs, methods of business, and local forms of government, the Achaemenids sought to maintain stability and secure the cooperation of diverse populations.12

This approach was a conscious effort by rulers such as Cyrus the Great and Darius I to balance imperial demands with local social structures. For example, Cyrus famously allowed Jewish captives in Babylonia to return to their homeland and supported local customs, such as sacrificing to local deities, which helped him be accepted as a legitimate successor in conquered territories.23

This relative permissiveness facilitated the administration of the empire, as it reduced the likelihood of national rebellions and encouraged local populations to view the central administration as mutually beneficial. While lapses in this policy occurred—such as when Xerxes I reacted violently to rebellions in Babylon—the early Achaemenid period was generally characterized by this flexible and inclusive style of rule.24