Meaning of "P" on Justinian I 16 Nummi

[Paul B4]

What does the "P" stand for on the reverse of this 16 nummi of Justinian I?
If P = 100 then one hundred of what?
I understand that the "A" is the officina and the "IS" indicates 16.
8.09 g, 23.3 mm
Thank you.

[SC]

According to Hahn, in MIBE, p.64, there is no clear answer.

He notes that there are also rare versions of the type from Thessalonica with AISPI and AISP .

He notes that several theories have been put forward to explain the AP:

argyron (currency) by Grierson,

archaia rhope or antiquo pondere (referring to a weight standard) in MIB I, and

ad pecunium (plus S for scrinium) by Hendy.

However, Hahn believes the the most probable is arca praefectura (plus I for Illyrici) denoting the office responsible for the production or provision of the metal, as suggested by Kent.

The AP are also found on either side of other denominations:  , H, B and I.

The A is unlikely to be an officina mark as no other letters is ever found.  If Thessalonica only had one officina at that time then why note the A, and if it had more than where are the other examples.  This is despite the fact that it is true that no officina mark appears in the exergue, which always has TES.  But that was common at Thessaloniki, even in the 4th century.  That is why Hahn did not include it in the list of possibilities.

SC

[Paul B4]

Thank you for this thorough explanation.

[Abu Galyon]

The problem of the  --- letters remains unsolved and I don't really think any of the conjectural solutions is particularly compelling. But the existence of the  ---  variant suggests to me that the answer will be found in Greek not Latin. I suppose argyron might mean 'currency' in the generic sense, but the word literally means 'silver' so it's a very odd formulation to put on a base metal coin (and that still leaves the psi variation unexplained).

Bill R.

[Paul B4]

Thank you, Bill.
As much as I like to know the meaning of all inscriptions, sometimes we must be satisfied with "unknown".