I have been stumped by the mint for the the following AE4, and want to check that I am not missing something obvious!:
Obv: DN VALENTINANVS PF AVG, pearl diademed draped and cuirassed bust right Legend 1c
Rev: SALVS REI - PVBLICAE, Victory advancing left dragging captive etc., chi-rho monogram in left field
Weight 1.11 gm, diameter 11-13 mm
So all very standard so far - the 4-letter mint mark though seems to read RT[R?B?]R?S?]
Rome seems the closest, as it has a series of 2-letter mint marks RP, RT, RB etc. [RIC IX 64(a) - but legend 1b]
So either I have missed the obvious, or an unlisted issue ... ?