Great Paschal period
A period of 532 years, the interval between two “identical” years. In
concept, in any year the days of the month will fall on the same weekdays, and
the phases of the moon on the same dates, as they did in the year 532 years
ago. The period is based on two calendrical cycles:
- The solar cycle. The days of every
month in a year fall on the same day of the week as the days did in the year one
solar cycle ago. In the Julian calendar, used from 46 bce
to 1582, the solar cycle is 28 years. If the 4th of July was a
Tuesday in 1400, in (1400 + 28) 1428 the
4th of July will also be a Tuesday.
- The lunar cycle. In any year, the phases of the moon fall on the same days of the month
as they did in the year one lunar cycle ago. The lunar cycle used in the Middle
Ages was the Metonic cycle of 19
years. Actually 19 years is only a close approximation, but generally
speaking, if there was a full moon on 6 August 1300, there will be a full
moon on 6 August in 1319.
Nineteen not being a factor of 28, 532 years have to pass (19 × 28 =
532) before both cycles complete at the same year.
This period has been variously called:
- the Victorian period, after
Victorius of Aquitaine, a 5th century advisor to
- the Dionysian period, after
Dionysius Exiguus, the 6th century monk who
established the Christian era by specifying the year of Christ's birth.
- the Great Paschal period, because it was a key parameter in calculating
the date of Easter.
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Last revised: 8 November 2003.