I would like to know how the days of the week were in the Ancient Middle East. Today we have fixed calendar days (Sunday - Saturday), but how was it back then? Has it always been the same? In the days of King David or Nebuchadnezzar II how would they know what day was day 1,2, or 3?
I am interested in the Biblical system, Babylonian system, etc. Any relative feedback is welcome. Thank you.
I can speak about the Babylonian methods of dating in the Neo-Babylonian, Achaemenid, and Seleucid periods (roughly 626-150 BCE). In the legal documents of Babylonia from these periods, scribes would date documents by day number and month. For instance, 23rd day of Ululu, or 1st day of Addaru, etc., then in the year of whatever king reigned at that time This site has a handy table and converter for the dating system of this period. There were no day names (like Saturday, Wednesday, etc.) or a concept of weeks, at least in these texts.
So, a full dating sequence in the Seleucid house deed would read like, "23rd day of the month Addaru, 2nd year of the king Antiochus."