In America, we have shortened it to "When in Rome..." We only say these three words. It is not said about Rome though. It is said about any place whee things are different. If you got to a friends house and they all take off their shoes "when in Rome..." you take off your shoes also. If you go on a trip and you are not sure how to act "When in Rome..." try to do what you see (but Americans are bad at seeing how to act. I know) We have a saying that claims we are trying. :) We just can't back it up with the correct actions.

As Glyn already pointed out, Rome is not special, the full 'motto' (short hint for living) being like this: If you are in Rome, live in the Roman way, if you are elsewhere, live as they do there Was originally written in Latin (father of the Italian language and precursor of several European languages)

When in Rome do as the Romans do It means when you are in a different country you must live by there laws. Way of life If you come to England and you do something here that to us is not good. I would say to you "When in Rome ( England ) Do as the Romans ( English people ) Do The Romans where here in the UK in 43 or 45 AD I forget now

"When in Rome, do as the Romans do." "Romas" means the gypsy community (the Roma/Romani people). A different meaning, there.