Luckily we got the International Organization for Standardization, so we don't have to rely on fickle gods anymore 
... and according to ISO 8601, Monday is the first day of the week.
This is super intriguing, thanks for sharing!
@lxo, in Vietnamese Monday to Saturday are literally number two to number seven, but I use an ISO date widget so it’s a math exercise every time I forget what day it is.
I don’t understand why you mentioned God though, @fribbledom: I’m not a Christian, but I’ve read Genesis out of curiosity and IIRC Jehovah took six days to create the world and spend the seventh day relaxing. I believe that Sunday being the first day of the week has a non-Christian root.
Obviously that's just a snarky comment I couldn't resist 
"For centuries the Romans used a period of eight days in civil practice, but in 321 CE Emperor Constantine established the seven-day week in the Roman calendar and designated Sunday as the first day of the week. Subsequent days bore the names Moon’s-day, Mars’s-day, Mercury’s-day, Jupiter’s-day, Venus’s-day, and Saturn’s-day. Constantine, a convert to Christianity, decreed that Sunday should be a day of rest and worship."