Gaius Cassius Longinus

"Among that select band of philosophers who have managed to change the world," writes David Sedley, "it would be hard to find a pair with a higher public profile than Brutus and Cassius – brothers-in-law, fellow-assassins, and Shakespearian heroes," adding that "it may not even be widely known that they were philosophers."[22]

Like Brutus, whose Stoic proclivities are widely assumed but who is more accurately described as an Antiochean Platonist, Cassius exercised a long and serious interest in philosophy. His early philosophical commitments are hazy, though D.R. Shackleton Bailey thought that a remark by Cicero[23] indicates a youthful adherence to the Academy.[24] Sometime between 48 and 45 BC, however, Cassius famously converted to the school of thought founded by Epicurus. Although Epicurus advocated a withdrawal from politics, at Rome his philosophy was made to accommodate the careers of many prominent men in public life, among them Caesar's father-in-law, Calpurnius Piso Caesoninus.[25] Arnaldo Momigliano called Cassius' conversion a "conspicuous date in the history of Roman Epicureanism," a choice made not to enjoy the pleasures of the Garden, but to provide a philosophical justification for assassinating a tyrant.[26]

Cicero associates Cassius's new Epicureanism with a willingness to seek peace in the aftermath of the civil war between Caesar and Pompeius.[27] Miriam Griffin dates his conversion to as early as 48 BC, after he had fought on the side of Pompeius at the Battle of Pharsalus but decided to come home instead of joining the last holdouts of the civil war in Africa.[28] Momigliano placed it in 46 BC, based on a letter by Cicero to Cassius dated January 45.[29] Shackleton Bailey points to a date of two or three years earlier.[30]

The dating bears on, but is not essential to, the question of whether Cassius justified the murder of Caesar on Epicurean grounds. Griffin argues that his intellectual pursuits, like those of other Romans, may be entirely removed from any practical application in the realm of politics.[31] Romans of the Late Republic who can be identified as Epicureans are more often found among the supporters of Caesar, and often literally in his camp. Momigliano argued, however, that many of those who opposed Caesar's dictatorship bore no personal animus toward him, and Republicanism was more congenial to the Epicurean way of life than dictatorship. The Roman concept of libertas had been integrated into Greek philosophical studies, and though Epicurus' theory of the political governance admitted various forms of government based on consent, including but not limited to democracy, a tyrannical state was regarded by Roman Epicureans as incompatible with the highest good of pleasure, defined as freedom from pain. Tyranny also threatened the Epicurean value of parrhesia (παρρησία), "truthful speaking," and the movement toward deifying Caesar offended Epicurean belief in abstract gods who lead an ideal existence removed from mortal affairs.[32]

Momigliano saw Cassius as moving from an initial Epicurean orthodoxy, which emphasised disinterest in matters not of vice and virtue, and detachment, to a "heroic Epicureanism."[33] For Cassius, virtue was active. In a letter to Cicero, he wrote:

I hope that people will understand that for all, cruelty exists in proportion to hatred, and goodness and clemency in proportion to love, and evil men most seek out and crave the things which accrue to good men. It's hard to persuade people that ‘the good is desirable for its own sake'; but it's both true and creditable that pleasure and tranquility are obtained by virtue, justice, and the good. Epicurus himself, from whom all your Catii and Amafinii[34] take their leave as poor interpreters of his words, says ‘there is no living pleasantly without living a good and just life.'[35]

Sedley agrees that the conversion of Cassius should be dated to 48, when Cassius stopped resisting Caesar, and finds it unlikely that Epicureanism was a sufficient or primary motivation for his later decision to take violent action against the dictator. Rather, Cassius would have had to reconcile his intention with his philosophical views. Cicero provides evidence[36] that Epicureans recognized circumstances when direct action was justified in a political crisis. In the quotation above, Cassius explicitly rejects the idea that morality is good to be chosen for its own sake; morality, as a means of achieving pleasure and ataraxia, is not inherently superior to the removal of political anxieties.[37]

The inconsistencies between traditional Epicureanism and an active approach to securing freedom ultimately could not be resolved, and during the Empire, the philosophy of political opposition tended to be Stoic. This circumstance, Momigliano argues, helps explain why historians of the Imperial era found Cassius more difficult to understand than Brutus, and less admirable.[33]

In Dante's Inferno (Canto XXXIV), Cassius is one of three people deemed sinful enough to be chewed in one of the three mouths of Satan, in the very centre of Hell, for all eternity, as a punishment for killing Julius Caesar. The other two are Brutus, his fellow conspirator, and Judas Iscariot, the Biblical betrayer of Jesus. It is unknown why the third ringleader of the conspiracy to kill Caesar, Decimus Brutus, was not also shown this deep in Hell.

Cassius also plays a major role in Shakespeare's play Julius Caesar (I. ii. 190–195) as the leader of the conspiracy to assassinate Caesar. Caesar distrusts him, and states, "Yond Cassius has a lean and hungry look; He thinks too much: such men are dangerous." In one of the final scenes of the play, Cassius mentions to one of his subordinates that the day, October 3, is his birthday, and dies shortly afterwards.

• Ariobarzanes III

• This article incorporates text from a publication now in the public domain: Chisholm, Hugh, ed. (1911). "Cassius s.v. 3. Gaius Cassius Longinus". Encyclopædia Britannica. Vol. 5 (11th ed.). Cambridge University Press. p. 461.
• Nodelman, Sheldon (1987). "The Portrait of Brutus the Tyrannicide". In Jiří Frel; Arthur Houghton & Marion True (eds.). Ancient Portraits in the J. Paul Getty Museum: Volume 1. Occasional Papers on Antiquities. Vol. 4. Malibu, CA, US: J. Paul Getty Museum. pp. 41–86. ISBN 0-89236-071-2.

• Cassius Dio Cocceianus (1987). The Roman History: The Reign of Augustus. Ian Scott-Kilvert, trans. London: Penguin Books. ISBN 9780140444483.
• Cicero, Marcus Tullius (1986). Selected Letters. D. R. H. Shackleton Bailey, trans. London: Penguin Books.
• Gowing, Alain M. (1990). "Appian and Cassius' Speech Before Philippi ('Bella Civilia' 4.90–100)". Phoenix. 44 (2): 158–181. doi:10.2307/1088329. JSTOR 1088329.
• Plutarch (1972). Fall of the Roman Republic: Six Lives. Rex Warner, trans. New York: Penguin Books.
• Plutarch (1965). Maker's of Rome: Nine Lives by Plutarch. Ian Scott-Kilvert, trans. London: Penguin Books.

Wikimedia Commons has media related to Gaius Cassius Longinus.

• "Cassius Longinus" in the Jewish Encyclopedia
• Letters to and from Cassius from Cicero's Letters to Friends
• "Life of Brutus"—from Plutarch's Parallel Lives