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) C. Fundanius 101 BC
Obverse: Laureate head of Jupiter right; C to left.
Reverse: Victory standing right, crowning trophy, beside which stands carnyx; before which, Gallic captive kneeling left; Q (mark of value) in exergue.
Ref: Crawford 326/2
Obverse: Laureate head of Apollo right, club (control mark) in left field.
Reverse: Victory advancing right, holding wreath and palm-branch, L PI - SO across fields, FRVGI in exergue.
Ref: Crawford 340/2e
(3) M. Porcius Cato 91 (89)BC
Obverse: head of young Bacchus or Liber right wearing ivy wreath, M·C(AT)O R
Reverse: Victory seated right, holding patera and palm VIC(TR)IX
Ref: Crawford 343/2b, SRCV I 248, Sydenh...
Obverse: head of Bacchus or Liber right wearing ivy wreath; M·C(AT)O·PRO·PR
Reverse: seated Victory right holding patera and palm; VIC(TR)IX
Ref: Crawford 462/2, SRCV I 1383, Sydenh...
(5) Octavian 27-29 BC
AR Quinarius Unknown mint
Obverse: CAESAR IMP•VII – Head of Octavian.
Reverse: ASIA RECEPTA – Victory draped, standing looking left, holding wreath in right hand. On cista mystica between two snakes
Ref: RIC 276, RSC 14
(6) Octavian 29-27 BC
Obverse: CAESAR IMP VII, Bare head of Octavian facing right
Reverse: ASIA RECEPTA, Victory standing facing left, holding wreath and palm, on top of cista mystica, serpents at left and right
Ref: RIC I (2nd Ed.) Augustus 276; RSC I...
(7) Rome | Anonymous 211-210 BC
AR Quinarius Apulia
Obverse: head of Roma right wearing crested helmet
Reverse: Dioscuri on horses riding right, holding spear and reins, stars over pilei; ROMA
Ref: Crawford 102/2d
Obverse: laureate head of Jupiter right, dot over N
Reverse: Victory standing right, holding wreath and palm. Trophy with Gallic captive seated left, T·CLO(VL)I, Q
Ref: Crawford 332/1b, SRCV I 212, Sydenh...