Epicurus' Birthdate

Why do we have three different birthdates for Epicurus?

The 7th

“Epicurus was born (as Laertius relates out of the Chronology of Apollodorus) in the 3rd year of the 109th Olympiad, the 7th day of the month Gamelion” (Gassendi, Epicurus, His Life and Doctrine 106, 1660)

“[F]or he was born on the 7th and dy’d on the 10th of the Month Gamelion” (Stanley, The History of Philosophy: Volume 3, 122, 1660)

“[A]fter the death of Epicurus they were to be perpetuated in memory of himself […] the anniversary of his birth, which fell on the seventh day of the month Gamelion” (De Witt, Epicurus and His Philosophy 104, 1954)

“First as to chronology. Of the authorities used in the Life far the best is Apollodorus, whose versified Chronology embodied the results of the great Eratosthenes. His data make it clear that Epicurus was born on the 7th of Gamelion (i.e. in our January) 341 B.C., and died in 270 B.C.” (Taylor, Epicurus, 18-19, 1911)

“Diogenes Laertius (10:14) also records a tradition that placed Epicurus’ birthday on the seventh of Gamelion. On the confusion (ancient and modern) between the gathering on the twentieth of every month and the celebration fo Epicurus’ birthday on the tenth of Gamelion, see Clay 1986 and Sider 1997: 152-53 and 156. Cicero (Fin. 2.101) and Pliny (HN 35.5) differentiate between the two” (Gordon, Then Invention and Gendering of Epicurus 30, 2012)

“He was born, according to Apollodorus in his Chronicles […] on the seventh day of the month of Gamelion, seven years after the death of Plato.” (Mensch, Lives of Eminent Philosophers 498, 2020)

The 10th

“Another part went to defray the expenses of the social meetings held annually on the anniversary of the birthday of Epicurus (the 10th of the Attic month Gamêlion)” (Wallace, Epicureanism 66)

“[T]he annual gathering of the group to celebrate his birthday on the tenth of Gamelion (in January).” (Clay, The Cambridge Companion to Epicureanism 22)

“Epicureans are to observe: Epicurus’ birthday on the tenth of the month Gamelion” (Gordon, Then Invention and Gendering of Epicurus 30)

“The Will provides (a) for an annual celebration of the birthday of Epicurus on the tenth of Gamelion (his birthday was actually on the seventh, according to Diog. Laert. 10.14)” (The Greek Anthology: The Garland of Philip and Some Contemporary Epigrams 394)

The 20th

“He was born on the twentieth of the month of Gamelion (24 january 341) […] The debate over the exact date of his birth was definitively resolved by Alpers 1968.” (Algra, The Cambridge History of Hellenistic Philosophy 43

“There were two rites for Epicurus: one annual, the twentieth of Gamelion, his birthday, and one on the twentieth of each month...” (Dorandi, Oxford Handbook of Epicurus and Epicureanism 58)

“Cf. Plut., Adv. Col. 1117AB. Epicurus’ birthday was commemorated each year and the twentieth day of each month was celebrated in honour of Metrodorus and later also of Epicurus himself. Cf. De Witt, Epicurus 105.” (Rist, Epicurus: An Introduction 11, 1972)

“[F]or conducting the customary birthday feast for us every year on the twentieth of Gamelion” (Epicurus, Lives of Eminent Philosophers translated by Stephen White 417, 2021)

"Sloppy commentary" is exactly right. I think this is what happens when secondary sources cite each other over source material. It seems to me that Epicurus' birthday may have been posthumously celebrated (after centuries) on the 20th as an extension of the monthly Eikas celebration. That, however, does not mean that he was born on the 20th of Gamelion, only that his birthday was celebrated in accordance with the monthly Eikas festival.

I am comfortable ruling out the 20th as a reflection of his historical birthdate. I think it is a symbolic custom. Who started that custom is also of interest, as they may not have had access to Epicurus' Last Will.

As to the differences between the 7th versus the 10th, Epicurus, himself, refers to the "customary celebration of my birthday on the tenth day of Gamelion in each year", whereas ancient authors like Diogenes agree that he was born on "seventh day of the month of Gamelion". I tend to think that one may have favored a historical birthdate as opposed to a celebration that has been tweeked to accommodate an occasion (like celebrating your birthday on the weekend).

My question, now, is this: is the usage of "customary" in Epicurus' Will a reflection of a symbolic celebration, moved in accordance to some other occasion? Or is this a technical description of his actual birthdate?

I note that Diogenes documents both dates (the 7th and the 10th) within one page of each other, the first one being a citation to Apollodorus, and the second being a citation of Epicurus' Last Will: “He was born, according to Apollodorus in his Chronicles, in the third year of the 109th Olympiad, during the archonship of Sosigenes, on the seventh day of the month of Gamelion, seven years after the death of Plato" (498). And then, one page later, "[T]he customary celebration of my birthday each year on the tenth of Gamelion.” (Mensch, Lives of Eminent Philosophers by Diogenes Laertius 499)

Since Both of these citations come from Diogenes, and they occur within a few paragraphs of each other, I think it is likely that the tenth is a symbolic custom, designated by Epicurus, and the seventh is the actual date of his birth.

The only proposition I have heard that corresponds with our Calendar comes from Alpers (about whom I could not find more information besides a citation from Alger) who proposes that the 24th of January corresponds with the 20th of Gamelion. So, if we are to take the 7th of Gamelion to be the actual date of Epicurus’ birth, then that should work out to January 11, 341 BCE. And then, the "customary celebration" of Epicurus' birth would fall on January 14, each year.

From my sources, I am drawing the following conclusions:

The 7th of Gamelion is the actual date of Epicurus' birth (Jan. 11th?)

The 10th of Gamelion is the date of celebration for those who strictly follow Epicurus' Last Will (Jan. 14th?)

The 20th of Gamelion is the date of celebration for the Eikadistae who merged his Birthday with Gamelion Eikas (Jan. 24th?)