Helena, AV Solidus, Sirmium. 

FL HELENA AVGVSTA, diademed, draped bust right
SECVRITAS REIPVBLICE, Securitas standing left, holding branch. 

Mintmark SIRM. 

RIC VII Sirmium 60; Cohen 11; Depeyrot 9/6; Sear 16586. 

From a Bank Leu auction, 2002.