This webpage belongs to www.janzuidhoek.net
and shows section Summary of [J. Zuidhoek (2019) Reconstructing Metonic
19-year Lunar Cycles (on the basis of NASA’s Six Millennium Catalog of Phases
of the Moon): Zwolle].
Summary
The development of the Metonic 19-year lunar cycle formed the
mainstream of the history of the computus paschalis which had risen in third
century Alexandria (Egypt) and would in 1582 flow out into the modern method which
since then is used in order to determine the Gregorian calendar date of Easter.
Between the active construction of the first version of this lunar cycle by
Anatolius (somewhere between AD 250 and 270) and the replacement of the Julian
with the Gregorian calendar (in 1582) it happened only one time, namely
somewhere between AD 300 and 325, hence still before the first council of
Nicaea, that a new version of it was actively constructed. After having
reconstructed (on the basis of NASA’s Six Millennium Catalog) the two lost
ante-Nicene versions in question, we establish that:
1) the first of them (referred to as ‘Anatolius’ 19-year
lunar cycle’) is nothing but the proto-Alexandrian 19-year lunar cycle
(reconstructed ten years ago);
2) the second (referred to as ‘the archetypal 19-year lunar
cycle’) must considered to be the archetype from which after AD 325 one after
another the three well-known post-Nicene Metonic 19-year lunar cycles were
obtained simply by moving only 1 of the 19 different dates of its predecessor
one day forward or back;
3) the cause of the 2-day gap between them (referred to as
‘the ante-Nicene Alexandrian 2-day gap’) must be sought in the transition from
the more Jewish Christian world of the third century to the more Gentile one of
the fourth, as a result of which Alexandrian computists went to use the more
familiar Egyptian lunar calendar instead of the Alexandrian version of the
Jewish lunar calendar.