If you visit a museum with Roman inscriptions and read the tombstones, you will notice that old people invariably died at 60, 70, or 80. The ancients didn’t know exactly how old they were (except, of course, for that man mentioned by Pliny the Elder, who said he could prove that he was 130 years old – from his tax records).
I wanted to check this, so I decided to look at the inscriptions from a city where many tombstones have been found. Mainz was a logical candidate: its Landesmuseum has a nice “Steinhalle” (hall of ancient stones). Besides, there were legions over here, which – I assumed – must have kept some kind of administration. I expected a more or less regular pattern with similar results for successive years until the late forties, when the soldiers left the army. After that I expected high peaks at 60, 70, 80, and lower peaks at 55, 65, 75.
The Epigraphik-Datenbank of Clauss and Slaby offered 2826 inscriptions, of which 245 contained formulas like “MIL LEG XXII PR AN XLVI STI XXI HSE” (= miles legionis XXII Primigeniae, annorum XLVI, stipendiorum XXI, hic situs est, “soldier of the Twenty-second Legion Primigenia, 46 years old, 21 years of service, is buried here”).
As the picture above shows, it did not work out as I expected, but still there is an interesting result. Between 20 and 50, there’s a peak every 5 year. After that, there is only a minor peak at 70. I deduce that the army kept no administration.
Among the other finds: the tombstone of a soldier who must have entered the army at thirteen (no unit mentioned, but a Roman citizen), the tombstone of an officer who served in four legions and apparently served 45 years, and some odd numerals like VL and XLIIX.