Believing the deliberate withholding of flatus to be unhealthy, Roman Emperor Claudius legalized the breaking of wind at banquets.
Of course, that's not what Suetonius (the source) said ... Divus Claudius 32:
Dicitur etiam meditatus edictum, quo veniam daret flatum crepitumque ventris in convivio emittendi, cum periclitatum qvendam prae pudore ex continentia repperisset.
"He is even said to have considered an edict ...". I'm sure even Suetonius recognizes tongue in cheek ... we should also point out that it never was illegal to fart at a dinner party ... still isn't (I hope).
In discussions on good manners, one should refer to Erasmus' 'De civilitate
morum puerilium' I have not yet read through to see what he has to say on
this particular point, although he deals with snot and sneezing.
FOLLOWUP: anyone know of an online version? I can't seem to find one ...