When was the Niederbieber Helmet put out of use?

[Nathan Ross]

There was a rumour of an example from Poitiers dating to around 270, but that turned out to be a gladiatorial helmet, I believe!

I tracked down the report on this helmet (actually two helmets), which was mentioned on the board here several years ago but is now available (in German) on Academia:

Jouquant-Thomas / Larcelet / Miks: Römische Helme aus einem mittelkaiserzeitlichen Siedlungskontext in Poitiers/Lemonum

The pictures are interesting even if you can't read the text. You can see how the excavators might originally have guessed that they'd uncovered a previously-unknown hybrid of a Niederbieber and a ridge helmet! But the gladiatorial version now seems to be accepted. It also goes to show how difficult it is to reconstruct fragmentary remains like this, and then interpret them correctly - and there seems to have been a lot more left of these helmets than the Novae one.