Week - Later use of the week

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

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

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