Lunar calendars
Before conventional months existed, time was counted by the Moon. This section tells how the great civilisations turned the phases of the Moon into calendars: from the scribes of Babylon who waited for the first crescent at sunset to the sages who fixed the Hebrew calendar, from the purely lunar Islamic calendar of the Hijra to the lunisolar systems of China and India. It covers the months of Athens and of archaic Rome, the Gaulish tablet of Coligny and the Anglo-Saxon month names preserved by Bede. Ample space is given to the computus, the medieval reckoning of Easter, and to the Gregorian reform, but also to living observances such as Ramadan and the Lunar New Year. The traditional names of the full moons are here too, with their real history, and so is the Ishango bone, presented with the caution that such a debated find requires. Every article draws on ancient sources and established scholarship, always distinguishing between documented facts, scholarly hypotheses and the stories of tradition.
The Babylonian calendar: lunar months and intercalary months in Mesopotamia
How the Babylonians counted time by the Moon: the months from Nisannu to Addaru, the first crescent, intercalary months and the nineteen-year cycle.
02 · 3 min readThe Hebrew calendar: from witnesses of the crescent to a fixed calculation
History of the Hebrew calendar: witnesses of the new Moon, the molad, the postponement rules, Adar I and Adar II and the nineteen-year cycle.
03 · 3 min readPassover, Sukkot and Purim: the Jewish festivals of the full moon
Why Passover, Sukkot and Purim fall under the full moon: the fifteenth day of the lunar month, Nisan and Tishri, Tu Bishvat, Tu B'Av and Kiddush Levanah.
04 · 3 min readThe Islamic calendar of the Hijra: twelve lunar months without corrections
The Hijri calendar: a 354-day year, the twelve months from Muharram to Dhu al-Hijja, the sacred months, the Hijra era of 622 and sighting the hilal.
05 · 3 min readRamadan: the ninth lunar month of crescent, fasting and festival
Ramadan in the Islamic calendar: sighting the hilal, the Night of Destiny, Eid al-Fitr and a fast that moves through every season of the solar year.
06 · 3 min readThe Chinese calendar: lunar months, solar terms and the sexagenary cycle
The Chinese lunisolar calendar: numbered months, the leap month, the twenty-four solar terms, the Taichu and Shoushi reforms and the cycle of sixty.
07 · 3 min readThe Lunar New Year: the Spring Festival in China, Korea and Vietnam
How the Lunar New Year is calculated, why it falls between January and February, Spring Festival customs, the twelve animals and the Lantern Festival.
08 · 3 min readThe Hindu calendar: tithi, nakshatra and intercalary months
The Indian lunisolar calendar: the tithi or lunar day, the two fortnights, the twenty-seven nakshatras, the amanta and purnimanta systems and adhika masa.
09 · 3 min readThe ancient Greek calendar: the months of Athens and the new moon
The months of the Attic calendar from Hekatombaion to Skirophorion, the noumenia, Hesiod's days of the month, the archons and the offended Moon of Clouds.
10 · 3 min readThe Metonic cycle: nineteen years to reconcile the Sun and the Moon
Meton and Euctemon, 235 months in 19 years, the period of Callippus, the dial of the Antikythera mechanism and the golden number of medieval calendars.
11 · 3 min readThe calendar of Romulus and Numa: the lunar origins of Roman time
The ten-month year credited to Romulus, Numa's reform with January and February, the month Mercedonius, the Fasti Antiates and Caesar's reform of 46 BC.
12 · 3 min readKalends, Nones and Ides: the phases of the Moon in the Roman month
Why the Romans counted days from the Kalends, Nones and Ides: the pontiff who called the month, the full moon sacred to Jupiter and Augustus's Greek Kalends.
13 · 3 min readThe Coligny calendar: the Moon in the time of the Gauls
The bronze tablet of Coligny, found in 1897: a Gaulish lunisolar calendar of 62 months, the MAT and ANM marks, the reports of Caesar and Pliny, and the doubts.
14 · 3 min readThe computus: how the Church learned to calculate the date of Easter
The rule of Easter after the spring full moon, Nicaea and Constantine's letter, Dionysius Exiguus and the Anno Domini, Whitby and Bede's great treatise.
15 · 3 min readThe Gregorian reform of 1582: epacts, moons and a corrected Easter
Aloysius Lilius, Christopher Clavius and the bull Inter gravissimas: ten days removed, epacts replacing the golden number, and the Orthodox Easter.
16 · 3 min readThe Quartodecimans: when Christian Easter followed the 14th of Nisan
The Quartodeciman controversy: the Churches of Asia and 14 Nisan, Polycarp and Anicetus, Pope Victor, Polycrates of Ephesus, Irenaeus and Nicaea's choice.
17 · 3 min readWolf Moon, Harvest Moon: the traditional names of the full moons
Where full moon names come from: the series of American almanacs, the Harvest and Hunter's Moons, and the real history of the Supermoon and the Blue Moon.
18 · 3 min readThe lunar months of the Anglo-Saxons according to Bede the Venerable
Chapter 15 of De temporum ratione: the lunar months of the ancient Angles, Modranecht, the Thrilithi year, Winterfilleth and the goddess Eostre behind Easter.
19 · 3 min readThe Ishango bone: a prehistoric lunar calendar? A note of caution
The Ishango bone, found in 1950 in the Congo: its notches, the prime numbers, Marshack's lunar hypothesis, the Lebombo bone and the limits of interpretation.
20 · 3 min readMoon and month: why the Moon was humanity's first clock
Synodic and sidereal months, the kinship of the words moon and month, lunar, lunisolar and solar calendars, the first crescent and days that begin at dusk.