Featured Epicurus’s Birthday: The 7th, 10th, or 20th of Gamelion - Mystery Solved

SUNDAY WEEKLY ZOOM - 12:30 PM EDT - Ancient Text Study: De Rerum Natura by Lucretius -- Meeting is open to Level 03 members and above -- Read the agenda for December 14, 2025 by clicking here.

File List

The EpicureanFriends Files section is where our Level 3 and above participants store longer documents created offsite which are of special interest to the study of Epicurus. You can use the "Categories" box on the right to find specific sections of the library.

This paper outlines the reasons to accept that Epicurus was born on the 20th day of the month of Gamelion.

The date of Epicurus's birth has been a source of confusion and debate since at least the 1800s; however, the evidence for a clear and consistent date has been in plain view all along.

There are good reasons to accept that the date of Epicurus's birth in Apollodorus' Chronicle referenced by Diogenes Laertius in The Lives and Opinions of Eminent Philosophers (LOEP 10.14) should be translated as "in the seventh month of Gamelion" and not "on the seventh day of the month of Gamelion" as numerous scholars have proposed.

Additionally, it has been shown that τῇ προτέρᾳ δεκάτῃ τοῦ Γαμηλιῶνος in Epicurus's Will refers to the 20th day of the lunar cycle in the ancient Athenian calendar and not to the tenth day of the month. A more literal translation would be "on 'the earlier tenth' of Gamelion."

In light of these corrections to the interpretation of the texts, there is reason to accept, with a high degree of confidence, that Epicurus's birthday was customarily celebrated annually on Gamelion 20 because that was his actual birthday. It is to this "Annual Feast of the 20th" (εἰκάδα δειπνίζων ἐνιαύσιον) to which Philodemus was inviting Piso in Epigram 11.44 in the Greek Anthology. It follows that the decision to choose the 20th of each month as the date for the monthly assembly of Epicurus's students would be in keeping with other monthly observances of the “birthdays” of “divine beings” in the Athenian calendar. In fact, Pliny the Elder, in his Natural History (35.2), states explicitly that Epicurus's birthday was celebrated every 20th of the month.

Furthermore, since the ancient Athenian month of Gamelion most closely matches January in the current Gregorian calendar, an optimal choice for modern Epicureans to keep to the spirit of Epicurus's Will would be to celebrate Epicurus’s Birthday on January 20 every year. If a "movable feast day" is desired to more closely adhere to the ancient calendar, one can use a reconstructed Ancient Athenian calendar such as the Hellenic Month Established Per Athens to celebrate the event on Gamelion 20.

The paper is also available on Internet Archive.

(For the forum thread that led to the writing of this paper, click here.)

June 19, 2025 at 1:00 PM

Thanks again for this great work, Don. I keep returning to it! I am trying to put the issue of the "earlier Tenth" in my own words, please let me know if you see anything objectionable:

The "earlier Tenth" refers specifically to the 20th day in a month with 30 days.

After the full moon, the Athenians switched to counting down from the end of the month. They referred to days as so-many days waning (i.e., remaining) in the month.

Also, in order to accommodate the variability between a 30-day and 29-day month, they duplicated the 10th waning day on months with 30 days.

On these months, the 20th and 21st were both referred to as "tenth" days – the 20th being the earlier tenth and the 21st as the later tenth.

Thus, the 20th day of the month was referred to as Εἰκάς (the Twentieth), and εἰκοστή (20th), and δεκάτη προτέρα (the earlier tenth) – and even just προτέρα (the earlier).

Finding Things At EpicureanFriends.com

Here is a list of suggested search strategies:

  • Website Overview page - clickable links arrranged by cards.
  • Forum Main Page - list of forums and subforums arranged by topic. Threads are posted according to relevant topics. The "Uncategorized subforum" contains threads which do not fall into any existing topic (also contains older "unfiled" threads which will soon be moved).
  • Search Tool - icon is located on the top right of every page. Note that the search box asks you what section of the forum you'd like to search. If you don't know, select "Everywhere."
  • Search By Key Tags - curated to show frequently-searched topics.
  • Full Tag List - an alphabetical list of all tags.