Gnaeus Calpurnius Piso (consul 23 BC)

Gnaeus Calpurnius Piso (fl. 1st century BC) was a high ranking Roman aristocrat and senator. He was firmly traditionalist and opposed the populist First Triumvirate, and later Julius Caesar. He fought against Caesar in the Caesar's civil war and against his adopted son, Octavian, in the Liberators' civil war; both times on the losing side.

He was twice pardoned, and subsequently retired from politics. He was unexpectedly appointed consul in 23 BC by the Emperor Augustus, whom he served alongside. In mid-term Augustus fell ill and was expected to die, which would, in theory, have left Piso as the highest authority in the state. In the event, Augustus recovered.