When in Rome, do as the Romans do

"When in Rome, do as the Romans do" (Medieval Latin: Sī fuerīs Rōmae, Rōmānō vīvitō mōre; sī fuerīs alibī, vīvitō sīcut ibī), often shortened to when in Rome..., is a proverb attributed to Saint Ambrose.^[1][2] The proverb means that it is best to follow the traditions or customs of a place being visited. A later version reads when in Rome, do as the Pope does.^[3]

This article is about the proverb. For other uses, see When in Rome.

Background

In the 4th century, Saint Monica and her son, Saint Augustine, discovered that Saturday was observed as a fast day in Rome, where they planned to visit. However, it was not a fast day where they lived in Milan. They consulted Saint Ambrose who said "When I am here (in Milan) I do not fast on Saturday, when in Rome I do fast on Saturday". That reply is said to have brought about the saying "When in Rome, do as the Romans do".^[4][5]