phrase
also: Roman History
also: Biblical & Christian
When in Rome, Do as the Romans Do
Adapt to local customs — the diplomatic proverb of every traveler and expat.
Origin
Attributed to St. Ambrose of Milan in the 4th century, who reportedly advised St. Augustine on whether to fast on Saturday in Rome (the Roman custom) or not (the Milanese custom): 'When I am here, I do not fast on Saturday; when in Rome, I fast on Saturday.' The compressed English form is fixed by the 16th century.
Modern usage
Standard etiquette advice for any cultural crossover — eating with hands, removing shoes, drinking what the host pours, switching languages. Quoted in study-abroad orientation, expat blogs, and any diplomatic-protocol guide. Sometimes weaponized to pressure outsiders into uncomfortable conformity.
Tags
customs
rome
diplomacy
proverb