Fascinating overstriking
Heraclius, with Heraclius Constantine (610-641). AE Follis. D/ Heraclius, on left, in military attire, holding long cross, and Heraclius Constantine, on right, holding globus cruciger, standing facing; cross above. R/ Large M; uncertain date across field; above, cross; below Γ; in exergue, CON. D.O. 107-16; Sear 810. 12.26 g. 33 mm. Interesting study coin. Overstruck on a Tiberius II follis. VF.