The 7-day week originated in Sumerian Babylon culture from 2100 BC and has to do with quartering moon phases. I worry when seeing many things attributed to "Judeo-Christian culture" which actually originated from other cultures, many aspects of what's in "Judeo-Christian culture" including perhaps some of the key stories in the Old Testament like the Flood appear to have been copied or at least inspired by stories from Sumerian culture which was considered the 'high culture' of the region.
How so? Constantinus was the one who committed to the change and the day names were after the Roman Gods. Even today, we're using Viking names, like today happens to be Odin's Day, tomorrow's going to be Thor's Day and the day after is going to be Freya's Day. I'm not sure it is reasonable or rational to "credit Christianity itself".
The Beatles were Romans!
1. The Romans had an eight day "week"; and,
2. The mesoamericans had a 260 day "week" (or, at best, interlocking 13 and 20 day "weeks").
I think the 7-day week is more of a statement about how effective the Judeo-Christian culture has imposed a modern week on the rest of the world.