Virtue ethics runs from Aristotle straight to Aquinas by one well documented route, its Christian reception. Aristotle's Nicomachean Ethics reached two other traditions covered elsewhere in this atlas by an entirely separate road, and neither Islamic akhlaq nor Jewish mussar owes anything to the Latin Christian transmission this entry otherwise tells.
Aristotle's ethical writings entered the Islamic world through the translation movement centered in ninth and tenth century Baghdad, rendered from Greek into Arabic, in some cases by way of an earlier Syriac intermediate translation, by scholars working independently of the Latin West and centuries before most of Aristotle's corpus reached Christian Europe in translation at all. Ibn Miskawayh drew directly on this Arabic Aristotle for the Tahdhib al-Akhlaq, keeping the doctrine of virtue as a mean between vicious extremes essentially intact while setting it inside an Islamic framework of scripture and law.
Moses Maimonides, writing in Judeo Arabic in twelfth century Egypt, inherited the same Arabic philosophical tradition, drawing on Aristotle both directly and through the intervening work of Islamic philosophers, and restated the doctrine of the mean for a Jewish audience in his own Shemonah Perakim, the Eight Chapters, treating the mean as a practical discipline for character rather than an abstract metaphysical claim. Three traditions this atlas records under akhlaq, mussar and, through Aquinas, Christian moral theology, arrived at recognizably the same Aristotelian architecture by three different routes, two of them running through Arabic and never touching the Latin manuscripts Aquinas actually read.