Darius I, also known as Darius the Great, was the third Persian King of the Achaemenid Empire. His reign lasted 36 years, time in which the Persian Empire reached its peak.
Under his rule, Persia went through a large transformation, evidenced in aspects associated with the government, improving the legal system by using the Babylonian Hammurabi as a model to design laws and even copying some of his laws completely. These were enforced by the judges of the empire, who needed to be incorruptible, system which was widely accepted.