Calpurnius Piso Galerianus was a man of the Calpurnia gens of ancient Rome who lived around the 1st century CE.
Gaius was married twice, to Livia Orestilla and later to Atria Galla, and it is unclear which of these women, if any, was Galerianus's biological mother.
We don't know exactly how old Galerianus was at this time, but he is described as "too young" to participate in the intrigues of this civil war, and despite being unremarkable and trying to live a quiet life -- the writer Tacitus describes him as having "no daring at all" -- his noble birth and his youth and popularity earned him the attention of the emperor Vespasian's prefect Gaius Licinius Mucianus, eager to quash potential threats to Vespasian's ascension.
This was possibly at least in part because a relative of Galerianus, Lucius Calpurnius Piso Frugi Licinianus, had been named heir by Galba himself.
Galerianus was arrested in Rome, led by armed guard for forty miles along the Appian Way, taken to a fortress and executed by injecting him with poison.