Seneca.

A Roman philosopher.

Attributed text(s).
Correspondence between Seneca and Paul.
The Pumpkinification of Claudius.
Many others (links below).

Available text(s).
Correspondence between Seneca and Paul (Latin and English).
Latin texts available at the Latin Library.
English translations available at Stoics.
The Pumpkinification of Claudius from Project Gutenberg (English only).

Related text(s).
Epistles of Paul.

Useful links.
Letters of Paul and Seneca (Homer D. Klong).
Quotes from Seneca (BrainyQuote).

Seneca was a Roman Stoic philosopher who flourished in Rome late in the middle of century I. The correspondence between Seneca and the apostle Paul is spurious, but was of great interest to many in medieval times.

Jerome, On Famous Men 12:

Lucius Annaeus Seneca Cordubensis, Sotionis Stoici discipulus et patruus Lucani poetae, continentissimae vitae fuit, quem non ponerem in catalogo sanctorum nisi me illae epistolae provocarent, quae leguntur a plurimis, Pauli ad Senecam et Senecae ad Paulum. in quibus, cum esset Neronis magister et illius temporis potentissimus, optare se dicit eius esse loci apud suos cuius sit Paulus apud Christianos. hic ante biennium quam Petrus et Paulus coronarentur martyrio, a Nerone interfectus est.

Lucius Annus Seneca of Cordova, disciple of the Stoic Sotion and uncle of Lucan the Poet, was a man of most continent life, whom I should not place in the category of saints were it not that those epistles of Paul to Seneca and Seneca to Paul, which are read by many, provoke me. In these, written when he was tutor of Nero and the most powerful man of that time, he says that he would like to hold such a place among his countrymen as Paul held among Christians. He was put to death by Nero two years before Peter and Paul were crowned with martyrdom.

Livio C. Stecchini and Jan Sammer have suggested that Seneca provides a testimonium to Jesus of Nazareth in his book On Anger (the footnote is theirs):

That Seneca had received some information about the founder of Christianity may be inferred from the allusion in one of his works to an unnamed individual who had aspired to royalty, but instead was condemned to suffer a cruel death upon the cross.*

* In his De Ira (I.2) Seneca lists six great men of the past who aspired to royalty but came to an evil end, the last being condemned to have his limbs split asunder upon a cross. The context indicates that this unnamed individual was of foreign nationality, and that his death occurred later than that of Pompey--hence within living memory. See Léon Herrmann, Chrestos (Brussels, 1970), p[ages] 41-43.

But this interpretation does not seem at all certain. Seneca writes in On Anger 1.2.2:

Aspice nobilissimarum civitatum fundamenta vix notabilia; has ira deiecit. aspice solitudines per multa milia sine habitatore desertas; has ira exhausit. aspice tot memoriae proditos duces mali exempla fati; alium ira in cubili suo confodit, alium intra sacra mensae iura percussit, alium intra leges celebrisque spectaculum fori lancinavit, alium filii parricidio dare sanguinem iussit, alium servili manu regalem aperire iugulum, alium in cruce membra diffindere.

Behold the foundations of the noblest cities which can scarcely be noted; anger cast them down. Behold deserted solitudes [going on] for many miles without inhabitant; anger wasted them. Behold so many leaders who have been handed down to memory as examples of an evil fate; anger stabbed one in his bed, struck another amidst the sacred laws of the table, tore another to pieces amongst the laws and as a spectacle for the crowded forum, forced another to give his blood by the parricidal act of his son, another to have his royal throat opened by the hand of a slave, another to have his limbs stretched upon the cross.

I asked for candidates for these six victims of anger on the FRDB (formerly the IIDB), and Jeffrey Gibson further submitted my inquiry to Classics-L, and the following are the suggestions for each victim:

• Stabbed in bed: Candaules by Gyges.
• Struck down at a banquet: Cleitus the black by Alexander of Macedon.
• Killed in the forum: Lucius Appuleius Saturninus by a mob.
• Parricide: The only suggestion was Oedipus as a sort of archetypal figure, but the one making the suggestion acknowledged that it seemed less apt than the suggestions for the rest of the list.
• Throat slit by a slave: Ptolemy of Mauretania on orders from Caligula.
• Crucified: Gavius by Verres, or Hannibal (a Carthaginian general, but not the famous Hannibal Barca) by his own men.

With at least two solid candidates for the victim of crucifixion, there is no call for assuming that the victim has to be Jesus.