P. Licinius Egnatius Gallienus, Roman Emperor A.D. 253-268 Gallienus was the son of the previous emperor Valerian I
The denomination is called an Antoninianus. It is an inflationary coin introduced by the Emperor Caracalla (198-217). Valued at two denarii, it only weighed 1 1/2 times as
much as a denarius. The spiked crown denotes the denomination. Later as bills had to be paid and more wars broke out along the frontiers, there was less and less silver in the coins, and the diameters shrank. Your coin looks like it was made earlier in the reign. Later issues became quite pitiful looking even when new.
The obv. : may be (E.) IMPCPLICGALLIENVSAVG (little hard to read)
The rev. : VIRTUS---AVG Roman cult figure representing "Courage" (Meaning our Emperor is brave)
There are so many variations of these. You can go to "wildwinds" and try to find the exact coin. Seaby's catalog shows a variety with obv. (A.) , GALLIENVSAVG
AVG = Augustus ...now used as a title.