where does saying when in rome come from
When in Rome, do as the Romans do Saint Monica and her son, Saint Augustine, found out that Saturday was observed as a fast day in Rome, where they planned to visit. It was not a fast day in Milan, where they lived. 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]
Speak of the devil Deriving from the Middle Ages, this proverb (which was, and to a certain extent still is, rendered as "Talk of the Devil...") was a superstitious prohibition against speaking directly of the Devil or of evil in general, which was considered to incite that party to appear, generally with unfortunate consequences. Its first printed usage in modern English can be found in Giovanni Torriano's Piazza Universale (1666), as "The English say, Talk of the Devil, and he's presently at your elbow."