Mos maiorum

The mos maiorum (Classical Latin: [ˈmoːs majˈjoːrʊ̃]; "ancestral custom" or "way of the ancestors"; pl.: mores, cf. English "mores"; maiorum is the genitive plural of "greater" or "elder") is the unwritten code from which the ancient Romans derived their social norms. It is the core concept of Roman traditionalism, distinguished from but in dynamic complement to written law. The mos maiorum was collectively the time-honoured principles, behavioural models, and social practices that affected private, political, and military life in ancient Rome.