Roman coin

[Aquila]

I have problem with this Roman i got last week from friend. Who is this dude in it?

 

[Silver Searcher]

The reverse is not very clear in the picture but it looks like a coin of Jovian :P

SS

 

[Mackaydon]

Where was the coin found?

 

[CRUSADER]

Looks like Constantius II with Obv showing DN CONST and an A behind bust like the obverse for an AQUILEIA mint. The Reverse is probably Soldier Spearing Fallen Horseman which would make coin a RIC VIII 193.

http://www.wildwinds.com/coins/ric/constantius_II/_aquileia_RIC_viii_193.jpg

'Constantius II Æ3. 352-355 AD. D N CONSTAN-TIVS P F AVG, diademed, draped & cuirassed bust right, A behind / FEL TEMP RE-PARATIO, soldier spearing falling enemy horseman, who is bare-headed (usually hair straight up), reaching backwards. LXXII in left field, S in centre, AQP to AQT in ex. '

 

[Silver Searcher]

Do you know what the letter is behind the bust there are a lot of second, and third century coins, that have a very similar bust the letter might help us to nail it

SS