Athenian Calendar and Festivals

Close up of statue Of Zeus.
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It's almost impossible to convert ancient Greek dates to a modern calendar, even approximately. Even our calendar isn't completely accurate: we celebrate festival events on Mondays rather than annually. Down the line, when future historians and archaeologists try to figure out what exactly or when something occurred, they may be aggravated by our lack of concern for exactness at the level of minutes. In the ancient world, the inaccuracy isn't a matter of minutes and seconds, so it seems more extremely wrong to us, but remember those future historians and be patient.

Among other problems, each city-state had its own calendar with its own system of dating.

A Full Month Intercalation

Typically, calendars have to insert a correction every over the months or years. We call it a leap year. This is really an "intercalated" ​day. In our calendar, the year is roughly 365 plus a quarter days long. Instead of having the year start six hours later each year, we add an entire "leap" day once in almost every four years.

The Greek lunisolar calendars of twelve months required an extra month periodically be intercalated to keep the calendar in line with the circuit of the seasons.

Regular Intercalation Isn't Enough 

Even with that leap day intercalation, there have to be periodic corrections. One extra day every four years is too much, so on certain, pre-assigned, four-year intervals, there is no extra day. The complicated astronomical knowledge used to generate this information was not available to the early calendar-workers (ancient priests), who needed calendars in order to observe the proper rites to honor the gods. They relied more on observation and tradition. We have trouble stripping away our modern assumptions. We believe in the accuracy of our particular variety of calendar-workers (scientists). We tend to forget that the calendar is not a single, universally agreed-upon set of dates, even though, in the modern world, Julian and Gregorian dates have not always coincided.


Stellar time from the ancient world really doesn't align with our modern calendars, so although it happened sometime in the July-August period, it's hard to date an event like the Panathenaic festival, which began when the constellation Draco rose above the Erechtheion on the Acropolis. Constellation "Draco" signaled the beginning of Athenian athletic festival new research shows].

Athens vs the Other Poleis

Athens is but one of the city-states, but it is the most familiar, so if you're looking for a list of the months of the generic ancient Greek calendar, the Athenian version may be what you want.

In the Athenian calendar, the intercalated month came after the annual month named Poseidon. It would have been known as Second Poseidon. We believe the Greeks alternated between 30- and 29-day months, resulting in what was basically a 354-day calendar. Some months are named for their festivals.

Calendars for Different Functions

By the second century B.C., there was a festival calendar and a lunar calendar. In addition to these two, there was a calendar for the government that is called the prytany calendar.

If you want to convert the Athenian Months to the modern calendar, you will have to consult a modern calendar or almanac or other references to determine the date of the new moon that follows the summer solstice—at least, that is what we think is the method of reckoning.

" All the officers of state, as well annual as those holding office for a longer period, when the new year is about to commence, in the month following after the summer solstice, on the last day but one of the year...."
Plato Laws Book VI

With the dates of the new moons, it becomes clear that the first month of the Athenian festival calendar, Hekatombion, began at some point between what is our late June to mid-July and ended on some day between late July and mid-August. From the start on about June 24 for 2012 to the start on July 13 for 2013, is more than 365 days, which is important in terms of reaching the summer solstice so the year-long festival system can restart. The Second Poseidon month might need to be inserted halfway through the year. To find the dates of the months takes guesswork, which I am not competent to do. We just don't know enough to convert with certainty. Look at successive years of the Hebrew calendar to see just how difficult it is for an individual to know when a given month starts. Since that calendar is still being used, we know the dates.

Months of the Athenian Festival Calendar

  1. Hekatombion: thought to have begun with the first new moon after the summer solstice. Kronia in honor of Cronus and Rhea; Synoikia possibly in honor of Athena and Eirene; Panathenaia in honor of Athena.
  2. Metageitnion: Heracleia in honor of Heracles; Eleutheria in honor of Zeus.
  3. Boedromion: Gemesia/Nemesia/Nekysia in honor of Gaia; Marathon celebration in honor of Artemis; Boedromia in honor of Apollo; Charisteria perhaps in honor of Athena; Eleusinia in honor of Demeter and Persephone; Asklepeia, in honor of Asclepius.
  4. Pyanepsion: Pyanopsia in honor of Apollo; Oschophoria in honor of Apollo; Theseia; Thesmophoria in honor of Demeter and Persephone; Apatouria in honor of Zeus Phratrios and Athena; Chalkeia in honor of Athena and Hephaestus.
  5. Maimakterion.
  6. Poseidon: Country Dionysia in honor of Dionysus; Haloia.
  7. Gamelion: Epilinaia in honor of Dionysus; Theogamia in honor of Zeus and Hera.
  8. Anthesterion: Anthisteria in honor of Dionysus; Lesser Mysteries in honor of Demeter, Persephone, and Dionysus; Diaisia in honor of Zeus Meilichios.
  1. Elaphebolion: City Dionysia in honor of Dionysus; Pandia in honor of Zeus.
  2. Munychion: Delphinia in honor of Apollo; Mounichia in honor of Artemis; Olympieia in honor of Zeus.
  3. Thargelion: Thargelia in honor of Apollo; Bendideia in honor of Artemis Bendis; Kallynteria in honor of Athena; Plynteria in honor of Athena.
  4. Skirophorion: Skira/Skiraphoria in honor of Athena; Dipolia/Disoteria in honor of Zeus Polieus.


Jon D. Mikalson "calendar, Greek" The Oxford Classical Dictionary. Simon Hornblower and Anthony Spawforth. © Oxford University Press 1949, 1970, 1996, 2005.

A Handbook of Greek Religion, by Arthur Fairbanks