Emperors Theodosius II and Honorius ban "amusements" on Sundays, even if it's an emperor's birthday.
According to this new law:
"On the Lord's Day, commonly called the Day of the Sun, We allow absolutely no amusements to be produced, even on the anniversary of the beginning of Our reign or the day when solemn rites are due to Our birthday." [CTh 2.8.25]
The holy days of other religions aren't accorded such respect, not even the sabbath of Judaism. It's only the Christian sabbath that gets set aside and protect from every other kind of diversion — almost as if the Roman government and Christian leadership are afraid that if people have the choice of what to do on Sunday, they might choose to do something other than go to church services.