Week - Facts and figures

A week is a unit of time longer than a day and shorter than a month. In most modern calendars, including the Gregorian calendar, the week is a period of seven days, making it the longest conventionally used time unit that contains a fixed number of days. Although having no direct astronomical basis, it is widely used as a unit of time. Weeks can be thought of as forming an independent continuous calendar running in parallel with various other calendars. However, some calendars have been designed so that a given date occurs on t ...

Including:

• Week - Origin of the seven-day week
• Week - Later use of the week
• Week - Facts and figures
• Week - Bibliography

Read more here: » Week: Encyclopedia - Week

In a Gregorian mean year there are exactly 365.2425 days, and thus exactly 52.1775 weeks (unlike the Julian year of 365.25 days, which does not contain a number of weeks represented by a finite decimal expansion). There are exactly 20871 weeks in 400 Gregorian years, so 25 December 1605 was a Sunday just like 25 December 2005. A system of Dominical letters has been used to determine the day of week in the Gregorian or the Julian calendar. ISO 8601 includes a numbering system for weeks; each week is associated with the year in w ...

See also:

Week, Week - Origin of the seven-day week, Week - Later use of the week, Week - Facts and figures, Week - Bibliography

Read more here: » Week: Encyclopedia II - Week - Facts and figures

Various groups of citizens of the Roman Empire adopted the week, especially those who had spent time in the eastern parts of the empire, such as Egypt, where the 7-day week was in use. Contemporaneously, Christians, following the biblical instruction, spread the week's use along with their religion. As the early Christians evolved from being Jewish to being a distinct group, various groups evolved from celebrating both the Jewish Sabbath (Saturday) and the first day or the Lord's Day (Sunday), to celebrating only Sunday. S ...

See also:

Week, Week - Origin of the seven-day week, Week - Later use of the week, Week - Facts and figures, Week - Bibliography

Read more here: » Week: Encyclopedia II - Week - Later use of the week