Herennius Senecio (d. 93 AD) was among the Stoic Opposition[1] to the emperor Domitian, under whose rule he was executed.
In 93 AD, Herennius and Pliny successfully prosecuted a case against Baebius Massa for improprieties during his administration in Baetica.
Baebius retaliated by bringing a charge of treason (maiestas) against Herennius, accusing him of impietas, but dropped the case when Pliny threatened a counter suit.
Because he had declined to run for any office after he was quaestor, he might be accused of desertion of public duty (secessio).
Helvidius's widow Fannia, the daughter of Thrasea Paetus, had given Herennius her late husband's notebooks (commentarii); for this she was also prosecuted by Carus and condemned to exile.