'PRAEFF' AND TWO LEGIONARY RANKS FOR L. ARTORIUS CASTUS

In the following recent blog post, I set out what seems to me the only possible reading for the ARM[...]S lacuna of the Castus inscription:

https://mistshadows.blogspot.com/2025/02/why-armoricos-reading-for-l-artorius.html?m=1

In short, the now accepted age for the stone (Severan), combined with a proper reading of it, forces us to ARMORICOS rather than ARMENIOS or any other proposed reading.

The only controversial portion of the text was PRAEFF. Generally considered a carving error (see below), I decided to take the word literally. 

The only possible translation for PRAEFF is "prefects." The question I then asked myself was how could Castus of been prefects of the same legion?

Well, this could only have happened when Perennis removed the legionary legates and installed equestrian prefects in their places. Agens vice legati does not seem to have existed until later, but according to Tomlin there are

"Plenty of instances before 200 of procurators and prefects pro legato."

We would thus have two separate ranks:

1) praefectus castrorum

and

2) praefectus pro legato

This could be expressed in shorthand as PRAEFF LEG(IONIS) VI VICTRICIS.

From Roger Tomlin on this idea:

"It's a good idea, and quite possible that he progressed from being Camp Prefect to deputising for the legionary legate (dead or temporarily absent or removed). But I would like to see an inscription which spelt out this progression.

I am not happy with PRAEFF meaning 'prefect twice' [as proposed by Malcor et al]. This would be spelt out with 'bis' or 'iterum'. So far as I know, PRAEFF is only used of an officer who is on the staff of the prefects (plural), especially the (two) Praetorian Prefects. I don't think it is even used of an officer who proceeds from being prefect of one unit to being prefect of another. You would have to find examples even of this. Centurions, for example, who transfer from one legion to another simply repeat the term. He doesn't call himself 'centurions' (followed by a list of legions).

And I would expect you to find me an instance of AVGG meaning 'Emperor twice'!

There is a bad error only two lines below, in BRITANICI|MIARVM. It's easy to miss a typo when you are reading what you expect to read. 

It's even possible that the offending F was plugged with plaster which has since been lost. But I don't think so. Instead it would be a mistake which goes back to the original layout (in charcoal?), when PRAEF was drafted like PRAEP immediately above. But then the stone-cutter, who knew that PRAEF was intended, mistakenly attached an E to A, mis-reading the next letter (E) as the final F?

A mistake – essential a muddle between E and F in the draft, by the stone-cutter mis-reading the cartoon someone else had prepared for him – is easier to suppose than a unique instance of PRAEFF meaning 'prefect twice'."

An alternate scenario would have the legates replaced by equestrians after Castus was sent to Armorica. The result, of course, would be the same: Castus would still be elevated from p.c. to p.p.l.