Five
Alexandrian Metonic 19‑year Lunar Cycles
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Anatolius 19‑year lunar cycle |
archetypal Alexandrian
cycle |
Festal
Index 19‑year lunar cycle |
Theophilus
19‑year lunar cycle |
classical Alexandrian
cycle |
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AD |
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304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 |
8 April 28 March 16 April 5 April 24 March 12 April 1 April 20 April 9 April 29 March 17 April 6 April 26 March 14 April 3 April 23 March 11 April 31 March 19 April |
6 April 26 March 13 April 2 April 22 March 10 April 30 March 18 April 7 April 27 March 15 April 4 April 24 March 12 April 1 April 21 March 9 April 29 March 17 April |
6 April 26 March 14 April 2 April 22 March 10 April 30 March 18 April 7 April 27 March 15 April 4 April 24 March 12 April 1 April 21 March 9 April 29 March 17 April |
6 April 26 March 13 April 2 April 22 March 10 April 30 March 18 April 7 April 27 March 15 April 4 April 24 March 12 April 1 April 21 March 9 April 29 March 17 April |
5 April 25 March 13 April 2 April 22 March 10 april 30 March 18 April 7 April 27 March 15 April 4 April 24 March 12 April 1 April 21 March 9 April 29 March 17 April |
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Table 8: Comparing the two
lost ante-Nicene and the three well‑known
post‑Nicene Alexandrian Metonic 19-year
lunar cycles to each other |
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Anatolius 19-year lunar cycle is the lost Metonic 19‑year lunar cycle from which the great
Alexandrian computist Anatolius,
bishop of Laodicea (Syria) from AD 268 to his
death in about AD 282, ultimately started in order to construct his famous
19‑year Paschal cycle. The archetypal Alexandrian 19-year lunar cycle,
also simply referred to as the archetypal Alexandrian cycle, is the lost ante‑Nicene
common archetype of the three well-known post‑Nicene Alexandrian Metonic 19‑year lunar cycles. Both of these Metonic 19‑year lunar cycles were both constructed
(before the council of Nicaea in AD 325) and
reconstructed (recently) mutatis mutandis according to four computistical
principles: the principle concerning the spring equinox, the principle
concerning the crescent moon, the principle of periodicity, and the principle
of metonicity.
The Festal Index 19-year lunar cycle,
also simply referred to as the Festal Index cycle, must have been obtained from
the archetypal Alexandrian cycle by replacing its date 13 April with
14 April. Theophilus 19‑year lunar cycle
must have been obtained by bishop Theophilus of
Alexandria by adopting the archetypal Alexandrian cycle or by adapting , or
correcting, the Festal Index 19‑year lunar cycle by replacing its date
14 April with 13 April. The classical Alexandrian 19-year lunar
cycle, also simply referred to as the classical Alexandrian cycle, is Annianus 19-year lunar cycle, being the Metonic 19‑year lunar cycle opted for by the
Alexandrian monk and great computist Annianus (in about AD 412) and subsequently adopted by
bishop Cyril of Alexandria (in about AD 425). The classical Alexandrian
cycle forms the Metonic structure underlying both Dionysius Exiguus Paschal table (composed in about AD 525) and Beda Venerabilis Easter table
(composed before or in AD 725).
We observe that there exists a gap of
about 2 days between on the one hand Anatolius
19‑year lunar cycle and on the other hand the other four Alexandrian Metonic 19‑year lunar cycles; this gap dates from
before the council of Nicaea in AD 325 (because
the archetypal Alexandrian cycle dates from before this council), and is
therefore referred to as the ante‑Nicene Alexandrian 2‑day gap.
©
Jan Zuidhoek 2019-2022