Cyropaedia is a biography of Cyrus the Great, the founder of Achaemenid Empire and the first Persian Empire.
It is a political romance, describing the education of the ideal ruler, trained to rule as a benevolent despot over his admiring and willing subjects.
Aspects of it would become a model for medieval writers of the genre known as mirrors for princes.
In turn it was a strong influence upon the most well-known but atypical of these, Machiavelli's The Prince.