Here is a seldom seen type that I was watching in the latest NN auction. It sold for 500 euros.
DIOCLETIAN (284-305). Antoninianus. Siscia.
Obv: IMP C C VAL DIOCLETIANVS P F AVG.
Radiate, draped and cuirassed bust right.
Rev: ROMAE AETERNAE / XXIΓ.
Roma seated to left on shield, holding Victory and sceptre.
RIC 276.