Who first improved on the Persian political and legal systems established by Cyrus the Great?

Cyrus the Great founded the Persian Empire and established systems for governing its peoples. Darius I later strengthened and improved those systems, including organizing the empire into provinces and refining its administration and laws. Herodotus was a Greek historian, Xerxes I was a later Persian king, and Zoroaster was a religious teacher.

AI-written and checked against the verified answer.