A brief orientation
Cyrus II — known to the Greeks as Cyrus the Great — founded the Achaemenid Persian Empire in the middle decades of the sixth century BCE. By the time of his death around 530 he had unified the Median and Persian peoples, defeated the Lydian king Croesus, absorbed the Babylonian Empire and become the ruler of the largest political body the ancient Mediterranean and Near Eastern worlds had yet seen. His son Cambyses, his successor Darius and the long imperial line that followed inherited a working administrative form his rule had established.
The two Cyruses
Two distinct Cyruses live in the surviving literature. The historical Cyrus is recoverable from Herodotus' Histories Book I, from the Cyrus Cylinder and other Near Eastern inscriptions, and from the Babylonian sources. The Greek philosophical Cyrus is the figure of Xenophon's Cyropaedia — a pseudo-biographical portrait of an ideal ruler that departs freely from what was already known about the historical king. The Cyropaedia is the work in which the European tradition read Cyrus most carefully, and it shaped how every later European thinker who knew the figure read him.
Why the classical tradition kept reading him
Cyrus is one of the few non-Greek figures whom the Greek philosophical and historical tradition treats with sustained admiration rather than with the suspicion it usually reserves for Eastern monarchies. The Cyrus Cylinder's policy of returning exiled peoples to their homelands and of leaving local religious customs intact gave the figure a reputation for moderation that the Old Testament prophets (Isaiah on Cyrus as God's "anointed") confirmed in a different register. Xenophon makes him the centerpiece of a long study of how a ruler is formed.
Why he matters for Virtue & Power
Cyrus is the platform's central case for empire as a political form the classical tradition could read with admiration rather than contempt. The pairing with Lycurgus, Solon and Numa places him in the lawgiver-founder grouping — he founded an imperial order rather than a civic one, but the moral architecture of his rule is what Xenophon writes about and what the European tradition received. See the essay Cyrus and the education of rulers.