1) The opinion of Rebbi Yochanan (27b) is that the reason the Anshei Ma'amad did not fast on Sunday is because of the "Notzrim," or Christians. However, there are a few different explanations of this in the commentaries.

2) Rabeinu Gershom (printed in the margin of the Gemara) writes that if Yisrael would fast on their festival day, they would become angry. According to him, the reason is a pragmatic one that related specifically to that time and place, and it is difficult to imply a general teaching from here regarding respect required for other religions. In additon, the commentary of Rashi on the Ein Yakov writes somewhat more sharply that if they would see Yisrael fasting they would be angry and we would be in danger as a result.

3) According to the latter explantion, it seems that life might be endangered as a result of fasting on Sunday. According to this explanation, this would be an example of the rule that saving life overrides all of the Mitzvos of the Torah (apart from the three cardinal sins), and one cannot prove from here what the Halachah would be if there is no threat to life.

4) I would go slightly further and claim that, at any rate according to Rabeinu Gershom, even if there would be no actual danger to life, it would still be justified not to fast on Sundays so that the Notzrim should not be angry. This is because the Mishneh Berurah (OC 330:8) cites opinions that one may transgress Rabbinical prohibitons in order to avoid "Eivah" (animosity) with the Nochrim. Eivah refers to a scenario where there is no direct danger to life, but nevertheless ill-feeling is involved.

5) If we consider what exactly the obligation was to fast on the days of the Ma'amad, we find that the Ein Yakov (beginning of fourth chapter, DH Yoshvin) writes that the reason why they fasted four days was in order that they should fast for the majority of the week. The Gemara explains that they did not fast on Fridays or Sundays simply to justify why they fasted four consecutive days rather than spreading the fast days more evenly through the week. It appears from this that according to the Halachah, the main thing is to fast four days in the week, but there is no basic requirement when those four days should be. If so, it follows that no prohibition is actually involved in not fasting on a Sunday. Therefore, if some opinions maintain that one can override a Rabbinical prohibition in order to avoid repercussions from the Nochrim, then one certainly can arrange that the Anshei Ma'amad will never fast on Sunday.

6) The Maharsha (DH Mipnei) gives yet another explanation for not fasting on Sundays. Since the Anshei Ma'amad did not do work on their fast day, it follows that if they would fast on a Sunday, they would also not do work on Sunday. This would make it look as if they agreed to the festival day of the Galilites (as the Maharsha calls them). Since Chazal did not want to make it look like we uphold their festival or Sabbath day, they wanted to make sure that everyone worked on Sundays.

Mendy, many thanks for your important question.

All the best,

Dovid Bloom

This is a very interesting topic. I do not claim to possess the necessary historical knowledge to deal with this properly but I am going to make a suggestion and please correct me if I have got the facts wrong.

1) The Meiri here writes that in fact the concern was about the Babylonians. This is the nation referred to in Yirmiyahu 4:16:- "The Notzrim are coming from a far-off country". Meiri writes that the name "NevuchadNetzar" is associated also with "Notzrim". He writes that they were very frightened of the Babylonians. The great sun-idol was worshipped widely at that time in Bavel and Sunday was the festival day. [He cites the acronym "ChaLaM TaZNaSh" according to which Sunday is the day of the Sun].

2) According to this, the Notzrim that Rabeinu Gershom and Rashi refer to could also be the Babylonians. In addition, even though the Maharsha refers to the Galilim, who appear to be what we refer to nowadays as the Notzrim, nevertheless he also writes that before the time of the Galilim, Sunday was a pagan rest day. Maharsha writes that even in the time of the first Beit Hamikdash, Anshei Mishmar did not fast on Sunday.

I ask, is it possible that the Babylonian sun-worship was the reason that in the times of the first Beit Hamikdash also they did not fast on Sunday?

3) The Chida, in his Chidushim on Ein Yaakov, asks your question about David and Shlomo, and because of this question he gives a different interpretation. However I suggest that possibly we do not have to say that the practice not to fast on Sunday went all the way back to the very beginning of the first Beit Hamikdash.

4) I also suggest that the commentaries considered that the people who we now call Notzrim, are in fact a continuation of the Babylonian Notzrim, at least with respect to the day they celebrate once a week. So, if would be true that the Notzrim had started to observe Sunday already in the time of Rabbi Yochanan, he might be referring to them as well.

5) Finally, I saw in Baalei Tosafot on the Chumash Bereshit 2:3, that the final letters of "Hashevi'I VayekadeSh OtO" are "Yeshu". This hints that he would uproot Shabbat and fix it on Sunday. This is why the Torah says that Hash-m blessed the seventh day, to warn us not to make the same mistake as them. [See B'Ikvei Yaakov by Rabbi Chaim Veizer p. 158].

KOL TUV

Dovid Bloom