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This
webpage is part of www.alexandriancomputus.net,
which supports the new book on early Alexandrian Paschal reckoning
[Jan Zuidhoek (2023) Reconstructing Alexandrian Lunar Cycles (on the basis of
Espenak’s Six Millennium Catalog of Phases of the Moon): Zwolle]. This
webpage displays all six Alexandrian Metonic lunar cycles treated in this new
book, which is available via this website. |
Six Alexandrian Metonic Lunar Cycles
The table shown here is a special
version of the never seen before Table 20 of this new book and
contains likewise in chronological order all three (lost) ante‑Nicene and all three (well-known) post‑Nicene Alexandrian Metonic lunar cycles:
The three (lost) ante‑Nicene Alexandrian Metonic lunar
cycles date indeed from before, the three (well‑known) post‑Nicene Alexandrian Metonic lunar
cycles from after the first council of Nicaea (AD 325), turning point in
the history of Christianity.
The three (lost) ante‑Nicene Alexandrian
Metonic lunar cycles, i.e. the proto‑Alexandrian
lunar cycle (0), Anatolius’ lunar cycle (1), and the archetypal Alexandrian
lunar cycle (2) (numbered in chronological order), were reconstructed only
recently by the author of the book in question. The proto‑Alexandrian lunar cycle (0) is by
definition the Metonic lunar cycle from which the great Alexandrian computist
Anatolius, who was bishop of Laodicea (Syria) from AD 268 to his death in
about AD 282, originally started to determine his Paschal dates, Anatolius’
lunar cycle (1) the one from which he ultimately started in order to construct
his famous 19‑year Paschal
cycle. These two early Alexandrian Metonic lunar cycles were constructed in the
third quarter of the third century and reconstructed respectively in 2009 and
2018, both on the basis of the principle “the spring equinox falls on
22 March” and the principle “the first day of a lunar month is the day
beginning with the sunset just before the first visible new crescent moon”
(according to the Alexandrian version of the Jewish calendar). Ultimately they
appear to differ in their saltus, as a consequence of Daniel Mc Carthy’s recent
revision of his interpretation of the eighteenth (AD 269) line of
Anatolius’ Paschal table.
The archetypal Alexandrian lunar
cycle (2) is nothing but the lost ante-Nicene common archetype of the three
(wrll-known) post‑Nicene Alexandrian Metonic lunar cycles. It was constructed in the
first quarter of the fourth century and reconstructed in 2018, both on the
basis of the principle “the spring equinox falls on 21 March” and the
principle “the first day of a lunar month is the first day after the day
beginning with the sunrise just after the last visible old crescent moon”
(according to the Egyptian lunar cycle).
The
three (well‑known) post‑Nicene Alexandrian Metonic lunar cycles, i.e. the
Festal Index lunar cycle (3), Theophilus’ lunar cycle (4), and the classical
Alexandrian lunar cycle (5) (numbered in chronological order), are related to,
respectively, the three important bishops Athanasius, Theophilus, and Cyril of
the church of Alexandria. The Festal Index lunar cycle (3) is the improvised
Metonic lunar cycle used by the very first compiler of the Festal Letters of
bishop Athanasius of Alexandria (AD 328‑373). Each of the three (well-known)
post‑Nicene Alexandrian
Metonic lunar cycles (3), (4), and (5) can be considered to have been obtained,
after Athanasius’ death in AD 373 and one after another, from the
archetypal Alexandrian lunar cycle (2) by accepting and whether or not adapting
it by moving its saltus one or two years forward or afterward. Theophilus’
lunar cycle (4), is the Metonic lunar cycle introduced by bishop Theophilus of
Alexandria (AD 384‑412) in order to structure his Paschal table of
100 years. The classical Alexandrian lunar cycle (5) is nothing but
Annianus’ lunar cycle, being the Metonic lunar cycle opted for by the
Alexandrian monk and great computist Annianus (in about AD 412) which sooner or
later would be adopted by the episcopacy of the church of Alexandria and
ultimately would become the Metonic structure underlying both Dionysius Exiguus’ Paschal table of 95 years, composed in about
AD 525, and Beda Venerabilis’ Easter table of 532 years, composed in
about AD 725.
We
observe that there exists a 2‑day gap (in fact a systematic difference of
on average just over 2 days) between the proto‑Alexandrian and Anatolius’ lunar cycle on the one hand and the
archetypal Alexandrian lunar cycle and the three post‑Nicene Alexandrian Metonic lunar cycles on
the other. The 2‑day gap in
question is referred to as the ‘(ante‑Nicene) Alexandrian 2‑day
gap’.
© Jan Zuidhoek 2023‑2025