Semis - Nero PONTIF MAX TR POT P P S C, Roma

Nero's semisses from this period were struck under the monetary reforms he initiated around 63–64 AD, which adjusted the weight standards of the aes coinage — part of a broader recalibration that also touched the aureus and denarius. The S C mark on bronze issues of the Principate denotes senatorial authority over the aes coinage, a constitutional fiction maintained long after it ceased to reflect any real political check on imperial minting decisions.

Nero's reign ended in 68 AD with his flight from Rome and suicide, triggering the Year of the Four Emperors and a near-total disruption of the imperial mint at Rome.