Sunday is day off from work
On March 3, 321 CE Roman Emperor Constantine the Great issued an edict which instituted Sunday (dies Solis, meaning “the day of the sun”) a day off from work in crafts and trade but did not prohibit agricultural work.
Offices were closed, except for those responsible for supervising the liberation of enslaved people.
The ordinance changed the week’s length (until now there was an 8-day week, the so-called nundinae) and sanctioned the Christian custom of celebrating the first day of the week (Sunday).