The Committee to Nuke Elysium

But whence the week? Throughout history, human societies have found it useful to divide time into groups of days shorter than a lunar month. One of the most common uses of this cycle has been to establish a regular market day, though just how regular varies. At one point, the Basques evidently employed a three-day week. For centuries, China, Japan, and Korea employed a 10-day week. Other societies have employed four-, five-, six-, eight-, and nine-day weeks.

So how did lucky No. 7 come to rule our calendars? It all began logically enough, when the ancient Babylonians divided their lunar months into four, yielding weeks that were mostly seven days. Then superstition kicked in. The final day of the week came to be considered evil or unlucky, and certain taboos developed around that day—against eating meat, for example.

It’s likely that the Babylonian week was the model for the seven-day Jewish week, with its own taboos against certain behaviors on the seventh day, or Sabbath. Babylon also probably served as the source of another important seven-day week used in Hellenistic Alexandria. The influence of that week remains with us in the names of heavenly bodies it assigned to each day—like Saturn-day, Sun-day, and Moon-day.

Meanwhile, the Romans marked time differently, which is why you never heard of anyone warning Caesar to “beware the third Tuesday in March!” Roman lunar months began on the Kalends, which scholars believe coincided with the new moon. The Ides, which fell on the 13th or 15th day of a month, coincided with the full moon. The Romans also kept an eight-day market week.

As Christianity—which kept the Jewish week but moved the Sabbath to Sunday—and Egyptian astrology gained influence in the empire, so did the seven-day week. Constantine, the first Christian emperor, made it official in 321. Since then, the spread of Christianity’s influence—as well as that of Islam, which also employs a seven-day week—has imposed the seven-day cycle on most of the world.

But there’s nothing inevitable about the ceaseless repetition of six days of work, one day of rest. As labor has become both more productive and more organized, the week has evolved. The writer Witold Rybczynski traces the emergence of the weekend to 19th century England, when the British agricultural revolution made land and labor more productive. At first, Rybczynski relates, this allowed workers extra leisure, which they enjoyed spontaneously—not according to any ironclad schedule. As the Industrial Revolution became a driving force in trans-Atlantic civilization, the push for greater efficiency demanded standardization of this extra leisure. In 1926, Henry Ford began shutting his factories on Saturdays in a bid to crystallize an American convention of a two-day weekend full of recreation (that he hoped would involve driving). It worked.