The Gregorian Calendar Reform

Because the average tropical year length is 365d24219878, each year the calendar slipped further behind the solar year. In 1000y, the difference was 7d8. By 1582 a.d., the difference became nearly 13d and the shifting date was creating some difficulties for the ecclesiastical calendar, especially for fixing the date of Easter. In that year, Pope Gregory XIII introduced a calendar reform that changed both the era base and the average length of the civil year. First, the date was advanced by 10d; the day Oct. 5,1582, became Oct. 15,1582. This moved the date of the vernal equinox back to March 21, where it was at the time of the Council of Nicaea, 325 a.d., when the formula21 for computing the date of Easter was adopted. Second, the average length of the year (over an interval of 400 years) became 365d2425; this was effected by restricting slightly the number of intercalary or leap years. Century years divisible by 400 (e.g., 1600 or 2000) would be leap years, whereas the intervening century years (e.g., 1700, 1800, and 1900) would not. Thus although there are 365.25 x 400 = 146,100d in four centuries of the Julian calendar, there are only 146,097d in four centuries of the Gregorian calendar. In Protestant and Eastern Orthodox countries, the Gregorian calendar would not be adopted until the 18th century or later. In England and its colonies, this occurred on September 3,1752, which became September 14,1752, in the Gregorian calendar. As in any other major civil occurrence, the calendar change caused an uproar; riots ensued in London as many people demanded their 11 days back. Preventive laws were enacted, but disputes over payment for services/commodities by the week, month, or year could have been at the heart of the discontent.

The onset of the year was altered at the introduction of the Julian Calendar by the intercalation of three months in 46 b.c. to bring the date of vernal equinox to a traditional value of March 25. That year, which had 446d, was called the "year of confusion." In Britain and its colonies, which had celebrated the start of the year on March 25, the introduction of the Gregorian calendar was preceded by starting the year 1752 on January 1. Therefore (in British jurisdictions), the year 1751 was only 282d long.

0 0

Post a comment