Antoninianus - Probus Draped and cuirassed, right; FIDES MILIT[VM]; Fides

Reverse

Fides standing left, holding long vertical scepter with her right hand and transverse signum with her left.
In exergue value mark (XXI) followed by officina mark (Є), sometimes officina mark in field.

Script: Latin

Lettering:
FIDES MILIT or
FIDES MILITVM

Unabridged legend: Fides Militum.

Translation: Loyalty of the soldiers.

Comment

RIC 151 was minted by the Rome mint. The original RIC text mentions 2 variations/different bust types (bust types according to Pierre Bastiens grouping of bust types; see illustrated: probvs.net), and also one variant is known to exist:

1. Radiate, draped, right (A bust (*), Guillemain (**) #28 (-/-//XXIЄ), example: probuscoins.fr #3069, Numista #214168);
2. Radiate, cuirassed, right (B bust, Guillemain #23(/53), #24 (exergue- field mark: -/-//XXIЄ), #25(/52) (-/Є//XXI), example: probuscoins.fr #200, Numista #294697);
3. [var] Radiate, draped and cuirassed, right (A2 bust (*), Guillemain #26 (-/-//XXIЄ), #27 (-/Є//XXI),example: probuscoins.fr #633, Numista #423213);

(*) RIC only lists the A bust (Probus, draped, right) and not also the A2 bust (Probus, draped and cuirassed, right) for RIC 151. See for example RIC 200 where the A2 and A bust are separately listed.

(**) Jean Guillemain, La Monetazione di Probo a Roma (276-282), Ripostiglio della Venèra-Nuovo Catalogo Illustrato Vol III/1, 2009.

RIC mistakenly lists that RIC 151 was minted by the 3^rd officina (officina letter: Γ), with exergue/field marks -/-//XXIΓ and -/Γ//XXI. As is clear from Pink, these style of exergue marks were only used by the Rome mint during the 1^st emission (year 276). See: Karl Pink, Der Aufbau der römischen Münzprägung in der Kaiserzeit VI/I, Wien, 1949, p. 55. According to Pink, during that emission, the 3^rd officina only minted ‘AEQVITAS AVG’ (= RIC 150), and therefore RIC probably copied the marks for RIC 151 by mistake from RIC 150. As is clear from Pink ‘FIDES MILIT’ was minted as part of the 1^st emission by the 5^th officina (letter: Є; exergue/field marks -/-//XXIЄ and -/Є//XXI), which corresponds with all examples listed by Guillemain and published on probuscoins.fr and probvs.net. This is also correctly pointed out by probvs.net: “RIC incorrectly lists #151 as from officina Gamma. They are from officina Epsilon only. cf. Pink, page 55.” Because in Numista exergue/field marks that are incorrect in RIC or differ from RIC are not included as a separate variant entry, the incorrect exergue/field marks have been corrected in the entries listed above (#214168, #294697 and #423213) by the correct marks. 

Note that Guillemain (#24) also lists two examples of a B bust, with exergue mark XXIЄ and reverse legend: ‘FIDES MILITVM’, unlisted by Pink.

Interesting fact