Justinian I. AE Follis 27mm, 17.50 g, Constantinople mint, AD 527-565. 

DN IVSTINIANVS PF AVG, pearl diademed, draped, and cuirassed 
bust right.
Large M; chi-rho to left, chi-rho above, chi-rho to right, Epsilon below. 

Mintmark CON. 
SB 162A; Paris 13; MIB 89. 

Very rare.

With permission of Ira & Larry Goldberg Coins & Collectibles, auction 55, Lot 300, Oct. 2009.