Radiometric dating lab exercise
Protestants and Eastern Orthodox countries continued to use the traditional Julian calendar and adopted the Gregorian reform after a time, for the sake of convenience in international trade.The last European country to adopt the reform was Greece, in 1923.The Gregorian reform contained two parts: a reform of the Julian calendar as used prior to Pope Gregory XIII's time and a reform of the lunar cycle used by the Church, with the Julian calendar, to calculate the date of Easter.The reform was a modification of a proposal made by Aloysius Lilius.To unambiguously specify the date, dual dating or Old Style (O. S.) even though documents written at the time use a different start of year (O. The Gregorian calendar continued to use the previous calendar era (year-numbering system), which counts years from the traditional date of the nativity (Anno Domini), originally calculated in the 6th century by Dionysius Exiguus. A regular Gregorian year consists of 365 days, but as in the Julian calendar, in a leap year, a leap day is added to February.S.), or whether a date conforms to the Julian calendar (O. In the Julian calendar a leap year occurs every 4 years, but the Gregorian calendar omits 3 leap days every 400 years.In Rome, Easter was not allowed to fall later than 21 April, that being the day of the Parilia or birthday of Rome and a pagan festival.The first day of the Easter moon could fall no earlier than 5 March and no later than 2 April.
In the modern period, it has become customary to number the days from the beginning of the month, and 29 February is often considered as the leap day.
Transition to the Gregorian calendar would restore the holiday to the time of the year in which it was celebrated when introduced by the early Church.
The reform was adopted initially by the Catholic countries of Europe.
By the 10th century all churches (except some on the eastern border of the Byzantine Empire) had adopted the Alexandrian Easter, which still placed the vernal equinox on 21 March, although Bede had already noted its drift in 725—it had drifted even further by the 16th century.
Worse, the reckoned Moon that was used to compute Easter was fixed to the Julian year by a 19-year cycle.