Ibn Miskawayh wrote the Tahdhib al-Akhlaq, the Refinement of Character, in Buyid era Iran in the late tenth century, and it became the founding text of philosophical akhlaq. His method was frankly Aristotelian: virtue is a mean between two vicious extremes, courage standing between cowardice and recklessness, generosity between miserliness and extravagance, and the virtuous life is achieved through habituation under the guidance of reason rather than through obedience alone. Miskawayh presented this as a medicine for the soul, borrowing directly from the language of Galenic physicians treating the body, and he wrote for an audience of educated courtiers and officials rather than jurists or theologians.
Akhlaq did not stay confined to that philosophical register. A century later, al-Ghazali's Ihya Ulum al-Din, the Revival of the Religious Sciences, absorbed the akhlaq genre's vocabulary of character and habituation into a programme of Sufi spiritual discipline, reworking Miskawayh's virtuous mean as a stage on the path toward nearness to God rather than an end in itself. Later advice literature for rulers carried the same framework into practical statecraft, treating a just ruler's character as the precondition for a just state.
The genre's range, courtly ethics, philosophical psychology, Sufi self discipline and mirrors for princes, is why akhlaq resists translation as a single English word. It names the whole discipline of forming a person's moral character, whichever institution, the court, the philosophical school or the Sufi lodge, was doing the forming, and its sources in Aristotle sit alongside its sources in the Quran and hadith without either being treated as the sole authority.