“When in Rome” is a vintage expression that may do for homiletic jargon what the Colosseum did for antiquity. Rome is so titrated out of the phrase that few people even think of the ancient city when they babble out the words, which are usually an injunction to conform. Do we need an archeologist of language to determine from whence “when in Rome” derives? Why not say “when in Syracuse” or “Ithaca” two names that like Rome are also now the names of cities in upper New York State. And why in hell did upstate towns ever get the idea of naming themselves after major cities of the Roman Empire? Was it simply grandiosity? Don Juan chasing windmills? But getting back to “when in Rome” Wikionary says the following about the origin of the expression: “First attested in medieval Latin si fueris Rōmae, Rōmānō vīvitō mōre; si fueris alibī, vīvitō sicut ibi (“if you should be in Rome, live in the Roman manner; if you should be elsewhere, live as they do there”); which is attributed to St Ambrose.” That’s definitely cool and makes a lot of sense, but it still doesn’t account for singling out Rome. Back in medieval times you might easily have said “when in Constantinople live in the Constantinoplian manner” or “when in Avignon (a place where one of the popes retired to), live in the Avignonian manner. Perhaps it goes back to the expression “all roads lead to Mecca,” since Rome was a mecca for medieval scholars like St. Ambrose. In any case, the expression is totally useless and even harmful to outsiders. As everyone knows, it’s impossible for someone who isn’t Roman “to live in the Roman manner.” Rossellini’s Roma, Citta Aperta deals with Rome during the Nazi occupation and God help you if you try to behave like Pina (Anna Magnani) or Don Pietro (Aldo Fabrizi) when you’re in Rome.