This type was issued after the appointment of new rulers in the Tetrarchic system and stressed that the loyalty of the military was unchanged. When this one was issued, the current lineup was Galerius and Severus II as Augusti and the Caesars were Maximinus II and Constantine I. It is rated as common in RIC, but actually seems a bit less than common.
Galerius
A.D. 306- 307
Ӕ Antoninianus
27x29mm 8.8gm
IMP C MAXIMIANVS P F AVG; laureate head right.
FIDES MILITVM AVGG ET CAESS NN, Fides stg. facing, head left, holding standard in each hand.
In ex. AQP
RIC VI Aquileia 76a