Kurdish calendar throughout Kurdistan follow the same principal structure for the "Kurdish days of the week". The Kurdish name for the first day of the week Sheme (Saturday) is in fact descended from Akkadian word Shabattu (In Sumerian Shabbât, Arabic Sabbath, Pahlavic Shunbat, Persian Shambed; Shamba; Shanbeh, even transferred to Greek as Sabbaton, German Samstag, Italian sabato, Spanish sábado, French Samedi). The Akkadian called the 15th day of the month, the day a full moon appears, Shabbattu. The question still remains why such an adoption was made for Kurdish and Persian days of the week. It has been documented that the Babylonian
Eight-day week popularity of the seven-day rhythm won and the eight-day week disappeared. The cycle of seven days, named after the sun, the moon, and the five planets visible to the naked eye, was already customary in the time of Justin Martyr, who wrote of the Christians meeting on the Day of the Sun (Sunday). Emperor Constantine eventually established the seven-day week in the Roman calendar in AD 321. The Celts used periods of darkness such as night and winter to begin their calculations of time. This meant that the first period of time in a "week" was a night, followed by