De Officiis Ministrorum (On the Duties of the Clergy)

Modeled explicitly and structurally on Cicero's De Officiis, three books addressed to the clergy of Milan by their bishop Ambrose, reworking Cicero's categories of honorable and expedient conduct around scriptural and specifically clerical examples in place of Cicero's Roman statesmen, arguing that Christian revelation, chiefly biblical figures like David and the apostles, supplies more reliable models of virtue than pagan philosophy's reasoning alone. Ambrose retains Cicero's basic architecture, the four cardinal virtues, the analysis of duty under difficult circumstances, while substituting a specifically clerical and monastic ethic, humility, chastity, care for the poor, for Cicero's civic and political ambitions, producing the first systematic work of specifically Christian clerical ethics in Latin. Written by the bishop whose preaching later helped convert Augustine, the treatise became, alongside Cicero's own original, a standard ethical textbook throughout the medieval Latin Church.