Bust of Libius Severus right / Monogram of Ricimer. 9mm, 0.64 grams. Rome mint? Cf. RIC X 2716-7.

Nice example, much better than most of these very crude coins. With a clear monogram, in a good style, probably the product of Rome rather than a military mint. These AE4s are traditionally attributed to Libius Severus (Severus III), with Ricimer's monogram on the reverse taken to show the power of Ricimer over the Emperor. 

Flavius Ricimer, a Patrician and Master of Soldiers, was a Romanized Germanic general who effectively ruled the remaining territory of the Western Roman Empire from 456 after defeating Avitus, until his death in 472.