Of course there are one or two people in that boat so I am not objecting of course.
meanwhile - in actual historic record we have this...
==========================
Cassius Dio (Lived 155-235 AD)
(describing Pompey’s conquest of Jerusalem in 63 BC) “16 Most
of the city, to be sure, he took without any trouble, as he was re-
ceived by the party of Hyrcanus; but the temple itself, which the
other party had occupied, he captured only with difficulty. 2 For
it was on high ground and was fortified by a wall of its own, and
if they had continued defending it on all days alike, he could not
have got possession of it. As it was, they made an exception of
what are called the days of
Saturn (Greek: tou Kronou de ono-
mas), and by doing no work at all on those days afforded the
Romans an opportunity in this interval to batter down the wall.
3The latter, on learning of this superstitious awe of theirs, made
no serious attempts the rest of the time, but on those days, when
they came round in succession, assaulted most vigorously. 4 Thus
the defenders were captured on the day of Saturn (Greek: tou
Kronou hamera), without making any defence, and all the
wealth was plundered... 3 They build to him a temple that was
extremely large and beautiful, except in so far as it was open and
roofless, and likewise dedicated to him the day called the day
of Saturn (Greek: hameran ten tou Kronou), on which, among
many other most peculiar observances, they undertake no serious
occupation” (Roman History, 37.16.1-4, 17.3).
(describing the Roman conquest of Jerusalem under Herod in 37
BC) “The Jews, indeed, had done much injury to the Romans, for
the race is very bitter when aroused to anger, but they suffered far
more themselves. The first of them to be captures were those who
were fighting for the precinct of their god, and then the rest on the
day even then called the day of Saturn (Greek: tou Kronou kai
tote hamera...). 5 And so excessive were they in their devotion
to religion that the first set of prisoners, those who has been cap-
tured along with the temple, obtained leave from Sosius, when
the day of Saturn (Greek: hamera authis he tou Kronou)
19
came round again, and went up into the temple and there per-
formed all the customary rites, together with the rest of the peo-
ple...” (ibid, 49.22.4-5).
(concerning Vespasian’s conquest of Jerusalem in 70 AD) “Yet
even under these conditions many captives were taken, among
them Bargiora, their leader; and he was the only one to be execut-
ed in connexion with the triumphal celebration. 2 Thus was Jeru-
salem destroyed on the very
day of Saturn (Greek: tou Kronou
hamera),
the day which even now the Jews reverence
most...” (ibid, 65.7.1-2).
================
The Bible says it was the first day of the week and calendar science tells us that the day we know as Sunday is the first day of the week in the Gospels.
The Julian Calendar came into use in 45 B.C. and from historic documents we know the relationship between Julian week days and Jewish days of the week used in the Gospels. So then we know the days of the week in ancient Rome at the time of Christ and how they map to our week days.
Sunday has been the first day and Saturday the seventh day since Roman times in the Julian calendar. Even non-Christian groups such as Jews know this ordering of the week and that the 7th day is Saturday making the first day Sunday.
==================
Has the 7-Day Week Cycle Ever Been Interrupted?
There is no record of the 7-day week cycle ever having been broken. Calendar changes and reform have never interrupted the 7-day cycles. It very likely that the week cycles have run uninterrupted at least since the days of Moses (c. 1400 B.C.E.), possibly even longer.
http://www.webexhibits.org/calendars/week.html#date
1. Has the 7 day weekly cycle ever changed?
a.
Week - Wikipedia
b. All Scholars agree that 1000 years BC – Israel used the same 7 day week that was being observed in Christ’s day and that it was very likely in use during the time of the Judges as well.
It is clear that among neighboring nations that were in position to have an influence over Israel – and in fact which did influence it in various matters – there is no precise parallel to the Israelite Sabbatical week. This leads to the conclusion that the Sabbatical week, which is as unique to Israel as the Sabbath from which it flows, is an independent Israelite creation.
[13][15]
The seven day week was widely known throughout the
Roman Empire by the 1st century AD,
[17] along with references to the Jewish Sabbath by Roman scholars such as
Seneca and
Ovid.
[19] The seven day cycle ultimately replaced the older Roman system of the
nundinal cycle, probably during the 4th century.
==============
But as you seem to suggest "what if all history and all scholars are wrong"?
