Yes, they're all Roman. Except for #1, they're all "late Roman bronzes", circa 300-400 AD.
#1: look like a Republican period silver denarius, circa 100 BC. The reverse looks severely damaged and the obverse isn;t much better, so I'm not sure it can be IDed better than that.
#2: a follis of Emperor Constans, reverse FEL TEMP REPARATIO with phoenix on pyre, mintmark unclear but probably Siscia.
#3: an emperor named Valentinian, not sure which one - the reverse is missing.
#4: two-Victories-and-shield type, but not sure of the emperor.
#5: Caesar Constantius Gallus, reverse FEL TEMP REPARATIO with soldier spearing horseman.
#6: reverse is Victory marching with wreath and the emperor's name begins with CONST... not sure which of several possibilities that could be.
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