Constantine IV Pogonatus, AD 668-685. AV Tremissis, 1.40 g, uncertain Italian mint. 

dN CONSTANTINYS PP AY, diademed, draped and cuirassed bust right. 
Rev. VICTORI-A [A]VGY I Delta, cross potent. Monogram in right 
field. Mintmark CONOB. 

MIB 49 (as Rome); Sear Byz 1228

With permission of Dmitry Markov Coins & Medals, Jan. 2016.
Estimate $300.