I recently bought this Maximian follis from Trier with the mintmark (as I read it) ITR. Clearly it's a Trier follis, but I'm not sure what the ITR means since the I can't be IOTA for a western mint at this time, right? If the I is really a 1, then why not write PTR for the prima officina? Are I and Prima (and II and Secunda) interchangeable officina marks? Is there a rhyme or reason governing the use of ITR vs. PTR? G.
I'm pretty sure that it's an I. And CA is right. According to the UK's Portable Antiquities Scheme, ITR and IITR both are attested mintmarks for Trier; I can only assume this is just an alternate way of writing first and second officinae at Trier. I'm happy to be corrected. https://finds.org.uk/romancoins/articles/page/slug/fourth-century-mints
