When was fasting prescribed for the nations before the Ummah of Muhammad (peace be upon him), during the time of which messenger, and what are the proofs for that?

The Almighty's saying: (O you who have believed, decreed upon you is fasting as it was decreed upon those before you that you may become righteous) [Al-Baqarah: 183] indicates the obligatory nature of fasting upon previous nations. However, no authentic hadith specifies which nations were first obligated to fast or the manner of their fasting. Nevertheless, there are sayings from the Salaf, among them: that it was the People of the Book, or three days of every month, or a full month. As for the fasting of Zachariah and Mary, peace be upon them, it was a fast from speaking.