As - Nero PONTIF MAX TR P IMP P P

Nero's aes coinage underwent a deliberate reform around 64 AD, reducing the weight standard that had held since Augustus — part of a broader monetary adjustment that also touched the silver denarius. The as in particular dropped noticeably in weight, meaning examples struck across this issue's production window can vary considerably, a factor worth noting when evaluating any given piece against the catalog weight.

RIC I 78 belongs to the Rome mint's output during a politically turbulent stretch that included the Great Fire of 64 AD and Nero's subsequent building program, both of which placed extraordinary demands on the imperial treasury.