[anjbe]

I’m actually really interested in this. Clearly in Jesus’s time the Hebrew week went Sunday–Saturday. That definition remained at least for long enough to make into Ecclesiastical Latin and further into, e.g., Portuguese (segunda-feira, etc.). So why does ISO 8601 go Monday–Sunday? Was it codifying existing practice in Europe? When did that practice begin? Was America colonized before Europe switched to Monday–Sunday, or is America’s Sunday–Saturday a fundamentalist reversion to something more Biblically accurate?

[mcv]

I live in Europe and I never learned anything other than that Sunday is the first day of the week. It's only very recently that I'm starting to notice an insistence that Monday is the first day. From my perspective, ISO 8601 seems to be the cause of that, and having an ISO standard on your side is certainly strengthening that position, but I think it's simply wrong.

Of course ISO 8601 didn't just drop out of thin air, but what caused it? I think it's a misunderstanding mixed with ignorance. Ignorance of the fact that the Jewish Sabbath, referred to everywhere in the Bible, is on Saturday, combined with people reading in the Ten Commandments about observing the Sabbath on the last day of the week and associating that with their own church attendance on Sunday, which they then conclude must be the last day of the week.

A more thorough reading of the Bible would have set them straight, as would some knowledge about history or other religions.

I actually used to think that Monday as the first day of the week was just a corporate thing. I first noticed it when I started working and work agendas were surprisingly insistent on starting on Monday. But I figured that was because the weekend is meaningless to the work week, so why not just lump it all together at the end? And then I learned about ISO 8601 and was completely flabbergasted that this was an official standard.

[anjbe]

Another commenter posted a source that mentions in passing that ISO 8601 was the result of a 1978 UN declaration that Monday should be the first day of the week. Now I wonder where that came from!