In the Gaian calendar, every date permanently falls on the same day of the week. The year always begins on a Monday (Sagittarius 1). The week is one of the longest-lasting institutions in human culture, predating most states, surviving calendar reform, empire, and religion.
Each day is named for a celestial body first systematized in ancient Babylon. In the Gaian calendar, Friday, Saturday, and Sunday form the three Sabbaths.