As Bruun points out in RIC, the neat things about the coins of the Caesars in this issue at
Alexandria are
(1) their
rarity: 1 recorded for
Crispus, 2 for
Licinius II, and now 1 for
Constantine II.
(2) the odd forms of their names, obviously because this was their first appearance in the coinage. No D N preceding their names, though this was normal from the next issue on; and
Licinius II gets
his praenomen CONSTANTINVS, "only rarely used".
(3) Finally, the appearance of the Caesars in this issue proves that the first civil war between
Constantine and Licinius took place in 316 not 314 as previously thought, because we know the Caesars were elevated on 1 March 317, but THE VERY SAME ISSUE at
Alexandria contains the very
rare coins of
Valens, whom
Licinius I made co-emperor during the war with
Constantine. An issue that certainly continued until after 1 March 317 is unlikely to have started any earlier than the year before, 316!