CONSTANTINVS IVN NOB CAES, diademed, draped and cuirassed small bust of Constantine facing right / CLARITAS REIPVBLICAE, Sol standing, chlamys across shoulder, holding globe, ASISI in exergue. 19mm, 2.8 grams. Siscia mint. RIC 37 note.The normal mintmark for these coins is ASIS. A number of different coins are listed in RIC 37 note with an additional mark after ASIS (like "I"). The last letter or symbol on this coin is either an "I" or perhaps a star. Interesting and very rare piece.