The Quinarius denomination
The quinarius was a small silver Roman coin valued at half a denarius.

Initially, the quinarius was struck for a few years, along with the silver sestertius, following the introduction of the denarius in 211 BC. At this time the quinarius was valued at 5 asses.

The coin was reintroduced in 101 BC as a replacement for the victoriatus, this time valued at 8 asses due to retariffing of the denarius to 16 asses in 118 BC.

For a few years following its reintroduction, large quantities of quinarii were produced, mostly for circulation in Gaul. The coin was produced sporadically until the 3rd century. It was also occasionally struck in gold.
Quinarius

(1) Allectus AD 294-296
Obverse: IMP C ALLECTVS P F AVG, radiate and cuirassed bust right, with decorated shoulder straps
Reverse: LAETITIA AVG, galley right, with mast and six oars; QC in exergue
Ref: RIC 124; Sear 12867
(2) Allectus 293-296 AD
Obverse: IMP C ALLECTVS PF AVG, Bust of Allectus facing right, wearing crown and cuirass
Reverse: VIRTVS AVG, Galley rowing left; QC mint mark in exergue
Ref: RIC V Allectus 128
(3) Augustus 25-23 BC
Obverse: AVGVST, Bare head of Augustus facing left
Reverse: P CARISI LEG, Victory standing facing right, crowning trophy of captured arms, dagger and curved sword at base
Ref: RIC I (Second Edition) Augustus 1b
(4) Augustus c. 25-23 BC
Obverse: bare head right; AVGVST
Reverse: Victory standing right, placing wreath on a trophy consisting of helmet and cuirass; dagger and sword hilt at base of trophy; P CARIS_I__LEG
Ref: RIC 1a; sear5 1642; RSC 386
(5) Caracalla 214 AD
Obverse: ANTONINVS PIVS AVG GERM, Bust of Caracalla facing right, wearing laurel wreath, cuirass, and drapery
Reverse: COS IIII P P, Victory advancing left, holding wreath and palm
Ref: RIC IV Caracalla 317a
(6) Galba 68-69 AD
Obverse: SER GALBA IMP CAESAR AVG P M T P, Head of Galba facing right, wearing laurel wreath
Reverse: VICTORIA GALBAE AVG, Victory wearing drapery, standing facing left on top of globe, holding wreath and palm
Ref: RIC I (Second Edition) Galba 131