the wife of Cn. Piso, who was appointed governor of Syria in A. D. 18 [PIso, No. 23], was probably the daughter of L. Munatius Plancus, consul B. C. 42.
She possessed all the pride and haughtiness of her hs9band, and while he used every effort to thwart Germanicus, she exerted herself equally to annoy and insult Agrippina.
She was encouraged in this conduct by Livia, the mother of the emperor, who hated Agrippina most cordially. On the return of her husband to Rome in A.D. 20, after the death of Germanicus. whom it was believed that she and Piso had poisoned, she was involved in the same accusation as her husband, but was pardoned by the senate in consequence of the entreaties of the empress-mother.
As long as the latter was alive, Plancina was safe, and she was suffered to remain unmolested for a few years even after the death of Livia, which took place in A. D. 29.
But being accused in A. D. 33, she no longer possessed any hope of escape, and accordingly put an end to her own life. (Tac. Ann. 2.43
; Dio Cass. Ivii. 18, 58.22.)