LYCOS RETRIEVER 
Julian Calendar: Gregorian Calendar
built 782 days ago
The Julian calendar, introduced by Juliius Caesar in -45, was a solar calendar with months of fixed lengths. Every fourth year an intercalary day was added to maintain synchrony between the calendar year and the tropical year. It served as a standard for European civilization until the Gregorian Reform of +1582.
Source:
[T]here was a 29February1900 in the Julian Calendar, but not in the Gregorian Calendar. This ensures that the Gregorian Calendar remains synchronized with the seasons for the next 10,000 years or so—without this change, Easter would fall in the summer time after the 100th century. However, this causes the difference between the calendars to increase with time. At present, the Julian Calendar is 13 days slow compared to the Gregorian Calendar.
Source:
Sweden decided to make a more gradual change from the Julian to the Gregorian calendar. Instead of taking 11 days out of the calendar in one year, it planned to drop a day every leap year from 1700 through 1740 until the eleven extra days were omitted. By 1740 it would be in line with the new Gregorian calendar and other countries.
Source:
The Julian and later the Gregorian calendars were designed to reflect the motion of the earth around the sun. The year is the actual length of time it takes for the Earth to complete one orbit around the Sun. The Gregorian calendar has a regular years = 365 days and a leap years = 366 days. The leap year (29 days in February) has one more day than a regular year (28 days in February).
Source:
The German astronomer Johann Heinrich Mädler proposed a calendar in 1864 which was supposed to replace the Julian calendar as well as the Gregorian calendar. The proposal suggested a 128-year cycle containing 31 leap years which was to have been achieved by omitting a leap year every 128 years, otherwise every fourth year being a leap year. The mean length of a year would have been 365+31/128 = 365,24219. Compared with the Gregorian calendar, this would have far better approximated the true length of the tropical year.
Source:
Pope Gregory XIII introduced the Gregorian Calendar in 1582 as a revision of the Julian calendar. He "suppressed" ten days because, by that time, spring was arriving on March 11th instead of the 21st, the time of the vernal equinox. Because the mean solar year is approximately 11 minutes shorter than 365 ¼ days, the Julian leap-year rule of "one extra day every 4th year" created three leap years too many in every 400-year period.
Source:
MORE ABOUT
Gregorian Calendar