How Old Was Epicurus When He Died?

I'm an Epicurean, not a mathematician, so I'm not confident with my numbers.

Even so, the dates and ages that Diogenes Laërtius presents do not add up (according to my calculations).

If Epicurus was born in the early months of 341 BCE, then his 72^nd birthday would have landed in the early months of 269 BCE (the 3^rd year of the 127^th Olympiad) and not 270 BCE (the 2^nd year of the of 127^th Olympiad). Therefore, it must either be the case that (a) Epicurus died when he was 71 (and not 72) during the archonship of Sosistratus, or else (b) he died in 269 BCE during the archonship of Pytharatus. Otherwise, Epicurus would have to have been born in the 2^nd year of the 109th Olympiad (early 342 BCE) during the archonship of Pythodotus (and not the 3^rd year [342-341 BCE] during the archonship of Sosigenes). Either way, Diogenes’ propositions that Epicurus (1) was born in the “third year of the 109th Olympiad [342-341 BCE] during the archonship of Sosigenes”, that (2) he died “in the second year of the 127th Olympiad, in the archonship of Pytharatus [271-270 BCE]” and that (3) he died “at the age of seventy-two” cannot all be true. Diogenes is either mistaking the dates, or Epicurus’ age.

Given the clarity of the archonships that Diogenes presents, which is supported by other authors, I suppose that Diogenes made an error: Epicurus died when he was 71 (not 72).

Quote from Don

Maybe he died the year he would have turned 72 but it was before his birthday that year?

I think that's likely.