Dienstag aus Licht Dienstag aus Licht Dienstag aus Licht (Tuesday from Light) is an opera by Karlheinz Stockhausen in a greeting and two acts, with a farewell, and was the fourth of seven to be completed for the opera cycle "Licht: die sieben Tage der Woche" (Light: The Seven Days of the Week). It was begun in 1977 and completed from 1988 to 1991, to a libretto by the composer. "Dienstag" is an opera for 17 solo performers (three singers, 10 instrumentalists, 4 dancer-mimes), actors, mimes, choir, orchestra, and electronic music. Tuesday is the red day of conflict between Michael and Lucifer .
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