Plancina was equally detested, but had stronger interest. Consequently
it was considered a question how far the emperor would be allowed
to go against her. While Piso’s hopes were in suspense, she offered
to share his lot, whatever it might be, and in the worst event, to
be his companion in death. But as soon as she had secured her pardon
through the secret intercessions of Augusta, she gradually withdrew
from her husband and separated her defence from his. When the prisoner
saw that this was fatal to him, he hesitated whether he should still
persist, but at the urgent request of his sons braced his courage
and once more entered the Senate. There he bore patiently the renewal
of the accusation, the furious voices of the Senators, savage opposition
indeed from every quarter, but nothing daunted him so much as to see
Tiberius, without pity and without anger, resolutely closing himself
against any inroad of emotion. He was conveyed back to his house,
where, seemingly by way of preparing his defence for the next day,
he wrote a few words, sealed the paper and handed it to a freedman.
Then he bestowed the usual attention on his person; after a while,
late at night, his wife having left his chamber, he ordered the doors
to be closed, and at daybreak was found with his throat cut and a
sword lying on the ground.

I remember to have heard old men say that a document was often seen
in Piso’s hands, the substance of which he never himself divulged,
but which his friends repeatedly declared contained a letter from
Tiberius with instructions referring to Germanicus, and that it was
his intention to produce it before the Senate and upbraid the emperor,
had he not been deluded by vain promises from Sejanus. Nor did he
perish, they said, by his own hand, but by that of one sent to be
his executioner. Neither of these statements would I positively affirm;
still it would not have been right for me to conceal what was related
by those who lived up to the time of my youth.

The emperor, assuming an air of sadness, complained in the Senate
that the purpose of such a death was to bring odium on himself, and
he asked with repeated questionings how Piso had spent his last day
and night. Receiving answers which were mostly judicious, though in
part somewhat incautious, he read out a note written by Piso, nearly
to the following effect:-

“Crushed by a conspiracy of my foes and the odium excited by a lying
charge, since my truth and innocence find no place here, I call the
immortal gods to witness that towards you Caesar, I have lived loyally,
and with like dutiful respect towards your mother. And I implore you
to think of my children, one of whom, Cneius is in way implicated
in my career, whatever it may have been, seeing that all this time
he has been at Rome, while the other, Marcus Piso, dissuaded me from
returning to Syria. Would that I had yielded to my young son rather
than he to his aged father! And therefore I pray the more earnestly
that the innocent may not pay the penalty of my wickedness. By forty-five
years of obedience, by my association with you in the consulate, as
one who formerly won the esteem of the Divine Augustus, your father,
as one who is your friend and will never hereafter ask a favour, I
implore you to save my unhappy son.” About Plancina he added not a

Tiberius after this acquitted the young Piso of the charge of civil
war on the ground that a son could not have refused a father’s orders,
compassionating at the same time the high rank of the family and the
terrible downfall even of Piso himself, however he might have deserved
it. For Plancina he spoke with shame and conscious disgrace, alleging
in excuse the intercession of his mother, secret complaints against
whom from all good men were growing more and more vehement. “So it
was the duty of a grandmother,” people said, “to look a grandson’s
murderess in the face, to converse with her and rescue her from the
Senate. What the laws secure on behalf of every citizen, had to Germanicus
alone been denied. The voices of a Vitellius and Veranius had bewailed
a Caesar, while the emperor and Augusta had defended Plancina. She
might as well now turn her poisonings, and her devices which had proved
so successful, against Agrippina and her children, and thus sate this
exemplary grandmother and uncle with the blood of a most unhappy house.”

Two days were frittered away over this mockery of a trial, Tiberius
urging Piso’s children to defend their mother. While the accusers
and their witnesses pressed the prosecution with rival zeal, and there
was no reply, pity rather than anger was on the increase. Aurelius
Cotta, the consul, who was first called on for his vote (for when
the emperor put the question, even those in office went through the
duty of voting), held that Piso’s name ought to be erased from the
public register, half of his property confiscated, half given up to
his son, Cneius Piso, who was to change his first name; that Marcus
Piso, stript of his rank, with an allowance of five million sesterces,
should be banished for ten years, Plancina’s life being spared in
consideration of Augusta’s intercession.
The Annals by Tacitus