Greek Calendar
Multilayered time woven polis by polis through lunar cycles. From Hesiod's star-husbandry to the bronze gears of the Antikythera Mechanism, from Athenian festivals to the birth of Hellenistic astrology in Alexandria. The conceptual homeland of the twelve zodiacal signs and the natal chart.
Why This Reconstruction?
In the Hellenistic period Alexandria assembled the largest known library of the world, its most accomplished mathematicians, and the priests who read the heavens most systematically. The centuries-long Babylonian lunar-planetary records, the thirty-six Egyptian decans and fixed-star maps, and the Greek genius for geometric abstraction converged here. The natal chart (genethliology), the twelve-house system, the doctrine of aspects, and the sign-planet-deity correspondences that spread throughout the Mediterranean are the products of this synthesis. The legend of Hermes Trismegistus is born at this very junction; the Greek Hermes blends into the Egyptian Thoth.
Yet in Greece there was no single calendar. Every polis used its own month names, festival year, and intercalation rule. Almost no month names overlap between Athens and Sparta; the Macedonian calendar operates on a wholly different logic from the Athenian. Despite this, the games convened every four years at Olympia, Delphi, Nemea, and the Corinthian Isthmus bound the entire Hellenic world to a shared cosmic rhythm. This cycle is the Olympiad; the Greeks' official way of reckoning time.
This tool rebuilds that system through the lens of today. The first new crescent after the summer solstice of the chosen year is calculated as Hekatombaion 1 of the Athenian calendar, and the twelve months follow in order. For each month the tool displays the Athenian festivals, the month-specific deities, the matching star entries from Hesiod's agricultural calendar of heliacal risings, and the three-decade lunar-phase naming system for the days. The Panhellenic Games cycle, the front and back dials of the Antikythera Mechanism, the birth-line of Hellenistic astrology, and the month names of other poleis appear in separate sections.
Many Greek words that have entered the modern English vocabulary are astronomical in origin: zodiac, planet, cosmos, astronomy, parapegma, heliacal. Classical astrology, that Greco-Egyptian-Babylonian synthesis, still speaks beneath our language.
The Twelve Months
The Athenian calendar; the best-documented Hellenic polis calendar. Each month begins on the evening when the first new crescent appears on the western horizon after the summer solstice. Click a month to see its festivals, lunar-deity associations, Hesiod's star records, and the three-decade naming of the days.
Hesiod's Stellar Calendar
Ἔργα καὶ Ἡμέραι; Works and Days. Circa 700 BCE, Boeotia. The annual cycle of the Greek farmer; marked not by month names but by the stars. The heliacal risings and settings of the Pleiades, Arcturus, Sirius, and Orion are the metronome of agriculture.
Panhellenic Games
A four-year cycle; the Olympiad. The common calendrical reference of the entire Hellenic world. A geared dial on the back of the Antikythera Mechanism tracks this cycle.
The Antikythera Mechanism
ca. 150-100 BCE. The earliest known analog astronomical computer. Recovered in 1900 by Greek sponge divers from a sunken Roman ship. With bronze gears it tracked the Sun, the Moon, the five planets, lunar phases, eclipses, the Metonic cycle, the Olympic cycle, and the heliacal risings of stars in its parapegma.
Front Dial · Solar-Zodiacal
- Outer ring Egyptian calendar, 12 months × 30 days + 5 epagomenai
- Inner ring Greek zodiac, 12 × 30°
- Pointers Sun, Moon, and five planetary positions
- Lunar sphere phase indicator (black-and-white)
- Parapegma heliacal risings of stars inscribed
Back Dial · Lunisolar Cycles
- Metonic spiral 19 years = 235 synodic months
- Callippic 76 years = 4 Metonic cycles
- Olympiad 4 years, Panhellenic Games
- Saros spiral 18-year eclipse cycle
- Exeligmos 54 years, triple Saros
The Birth of Hellenistic Astrology
After Alexander's conquest of Egypt in 332 BCE, the Babylonian-Egyptian-Greek synthesis was forged in Alexandria. The lineage from which the natal chart was born.
Other Polis Calendars
A comparison with Athens. Each city-state used its own month names; overlap is rare and any transfer is indirect.
| # | Athens | Sparta | Macedonia | Delphi | Approximate Season |
|---|---|---|---|---|---|
| 1 | Hekatombaion | Hekatombeus | Loios | Apellaios | Jul-Aug |
| 2 | Metageitnion | Karneios | Gorpiaios | Boukatios | Aug-Sep |
| 3 | Boedromion | (unknown) | Hyperberetaios | Boathoos | Sep-Oct |
| 4 | Pyanepsion | (unknown) | Dios | Heraios | Oct-Nov |
| 5 | Maimakterion | (unknown) | Apellaios | Daidaphorios | Nov-Dec |
| 6 | Poseideon | (unknown) | Audnaios | Poitropios | Dec-Jan |
| 7 | Gamelion | (unknown) | Peritios | Amalios | Jan-Feb |
| 8 | Anthesterion | (unknown) | Dystros | Bysios | Feb-Mar |
| 9 | Elaphebolion | Hyakinthios | Xandikos | Theoxenios | Mar-Apr |
| 10 | Mounichion | (unknown) | Artemisios | Endyspoitropios | Apr-May |
| 11 | Thargelion | (unknown) | Daisios | Herakleios | May-Jun |
| 12 | Skirophorion | (unknown) | Panemos | Ilaios | Jun-Jul |
In Sparta most month names are lost or disputed; the known ones derive from two principal festivals. The Macedonian names were carried into the Near East during the Hellenistic period with Alexander; they remained the official calendar of the Seleucid Empire.
Primary and Secondary Sources
- Hesiod, Ἔργα καὶ Ἡμέραι (Works and Days), ca. 700 BCE; trans. M. L. West, Oxford UP, 1988.
- Athenian calendar; J. D. Mikalson, The Sacred and Civil Calendar of the Athenian Year, Princeton UP, 1975.
- Athenian festivals; H. W. Parke, Festivals of the Athenians, Cornell UP, 1977.
- Panhellenic Games; D. G. Kyle, Sport and Spectacle in the Ancient World, Wiley-Blackwell, 2014.
- Antikythera Mechanism; T. Freeth and A. Jones, "The Cosmos in the Antikythera Mechanism," ISAW Papers 4, 2012.
- Antikythera front dial; Y. Bitsakis and A. Jones, The Front Dial and Parapegma Inscriptions, Almagest 7, 2016.
- Hellenistic astrology; C. Brennan, Hellenistic Astrology: The Study of Fate and Fortune, Amor Fati, 2017.
- Greek astronomy; J. Evans, The History and Practice of Ancient Astronomy, Oxford UP, 1998.
- Eleusinian Mysteries; W. Burkert, Ancient Mystery Cults, Harvard UP, 1987.
- Anthesteria; R. Hamilton, Choes and Anthesteria, Michigan UP, 1992.
- Ptolemy, Tetrabiblos, 2nd c. CE; trans. F. E. Robbins, Loeb Classical Library, 1940.
- Dorotheus of Sidon, Carmen Astrologicum, 1st c. CE; trans. D. Pingree, Teubner, 1976.
- Vettius Valens, Anthologiae, 2nd c. CE; trans. M. Riley (pdf), 2010.
- Lunisolar cycles and the Olympiad; C. Tuplin and T. Rihll (eds.), Science and Mathematics in Ancient Greek Culture, Oxford UP, 2002.