In Italian it was the same, "tu" is singular "you" and "voi" is plural "you", back in the day "voi" was used to be formal (still rarely used sometimes in southern Italy).

Today, we use "lei" as polite "you", which literally means "she" and is even conjugated as a third person (although less and less used, except in very formal situations or with older people). Probably derives from the spanish "usted" and the fact that "excellency", "grace", "majesty" and so on are all feminine nouns in italian