How did Cyrus and Darius 1 each rule diverse groups of people peacefully

Because they both had sense for justice

Explanation:

Cyrus the Great is equally recognizable as a statesman and a soldier. By pursuing a policy of generosity instead of repression and respect for other local religions, he was able to convert submissive peoples into his ardent followers.

Due to the political infrastructure he set up, the Achaemenid Empire remained long after Cyrus's death. Even his successor Darius I is remembered in historical books as the King with a sense of justice.