The First Triumvirate was an informal political alliance among three prominent politicians in the late Roman Republic: Gnaeus Pompeius Magnus, Marcus Licinius Crassus, and Gaius Julius Caesar.

In order to bypass constitutional obstacles and force through the political goals of the three men, they forged an alliance in secret where they promised to use their respective influence to support each other.

Amid even stronger backlash at Rome against the use of naked force and chaos to achieve political ends, Crassus died in 53 BC during his failed invasion of Parthia.

[3] Others add more reasons to avoid its use, for example, Robert Morstein-Marx in the 2021 book Julius Caesar and the Roman People, "it is almost impossible to use the phrase 'First Triumvirate' without adopting some version of the view that it was a kind of conspiracy against the republic... Nomenclature matters...

[12] The alliance between Pompey, Crassus, and Caesar emerged due to their failure to pass various core portions of their programmes in the gridlocked state of Roman politics in the years before 60 BC.

While he was successful in getting one of his men, Marcus Pupius Piso Frugi Calpurnianus, elected consul for 61 BC, an intervening religious scandal had made it impossible for him to push forward the appropriate land resettlement legislation.

[18] Lucullus returned from his semi-retirement to demand an in-depth review of every aspect of Pompey's eastern arrangements; "this would take a tremendous amount of time and would prevent passage of the bill for the foreseeable future".

[22] Those public contractors had massively over-bid on tax contracts for the province of Asia (parts of modern western Turkey) because they failed to account for the devastation of the Third Mithridatic War.

[23] Passing renegotiation of these tax contracts was vital for Crassus: "his reputation and influence depended on his ability to act as a champion for the powerful equestrian order".

[46] Caesar needed the alliance as well: he would fully become his own man, "escap[ing] the subordinate stature of Pompey's other amici", defeat the political opposition, and win a profitable command.

In general, that an agrarian bill was desirable and "well justified... could not reasonably be denied... many senators must have felt that it was not high time to make good on the promise made long ago to the long-suffering veterans".

[78] When Cicero, defending his former co-consul Gaius Antonius Hybrida, made an off-hand remark complaining about the political situation, his "deadly enemy P. Clodius [had] his long-obstructed 'transition' to the plebs rushed through by Caesar... in good time to stand for the tribunate".

[79][80] Caesar then moved to lift the exemption of Campania from his agrarian bill some time in May; its passage may have proved the last straw for Bibulus, who then withdrew to his house.

[96] Cato and Bibulus, for their part, mobilised a large propaganda campaign seeking to brand Caesar a tyrant, with "dire warnings of the impending overthrow of the republican government" that discredited the alliance and forced senators to re-evaluate their tacit support.

By early 56 BC, he had won enormous popularity both with the senate and the people: in 57, Caesar requested thanksgivings for his victory over the Belgae and, at a motion of Cicero, received fifteen days of supplicationes, a new record.

[147] While they certainly won a temporary victory, the longer-term fallout of intimidation tactics and the validation of Cato's warnings proved especially harmful "among the basically conservative Roman voters".

The main piece of legislation was brought by an allied tribune, Gaius Trebonius, to grant for five years Crassus and Pompey the provinces of Syria and Hispania (they would draw lots for the specific assignment).

[160] Cato and his coterie's judicial attacks were unsuccessful "in large part because the complex network of connections among senators meant that the litigants could not be reduced to stark choices between two political parties or ideologies".

Coupled with raging street battles in the city between Milo and Clodius' armed gangs, elections were finally held after more than seven months without any magistrates, in July 53 BC.

[172] As a whole, these various elections showed the weakness of the triumviral coalition: Caesar, Pompey, and Crassus were unable to produce consistently favourable results except when their aims were entirely united; the joint consulship in 55 BC was brought about by force and, "thereafter, their [the alliance's] stock with the voters rapidly depreciated".

Standing for the consulship in this year were Milo (supported by Cato and others), Publius Plautius Hypsaeus (one of Pompey's former lieutenants), and Quintus Caecilius Metellus Pius Scipio.

[181] The next day, his body was brought back to Rome, where a mob then stormed the senate house and burnt it down – along with the Basilica Porcia – as part of Clodius' funeral pyre.

[182] Shortly thereafter, the senate passed a senatus consultum ultimum which called for the interrex and Pompey, as proconsul, to raise troops and take them into the city to restore order.

[186] Also around this time, Pompey had married the daughter of Quintus Caecilius Metellus Pius Scipio, who also was the widow of Crassus' son; this was part of an attempt to win over more allies.

[189] During Pompey's sole consulship, he married Cornelia Metella, the daughter of Quintus Caecilius Metellus Pius Scipio, but this too was not a break with Caesar (as implied by Velleius Paterclus).

Pompey's marriage in 52 BC and his another law reaffirming the requirement to declare candidacy for office in person "did not actually harm Caesar directly" but indicated his willingness to build alliances with other, formerly closed off, political groupings.

[206] This veto, perhaps a mistake or possibly made with knowledge that Pompey was hostile to Caesar's standing for election in absentia with his army – which would have been seen as intimidating – started the crisis.

[207] Caesar, knowing that Pompey was reconciling with Cato and Bibulus, was unable to trust him to stick to his word, especially if giving up his command would open him to possibly having his candidacy and triumph rejected by the unfriendly consuls.

[6] Amy Russell, writing in the Encyclopedia of Ancient History, similarly focuses on how the alliance failed to dominate elections, viewing instead the accusations of regnum from Cicero and lamentations of tyranny as "deriv[ing] from their opponents' rhetoric... [who] at the same time... were working to divide them [the allies]".

[3] Similarly, Mary Beard says the alliance "was not such a complete takeover as those comments [from Horace and Cicero] imply[;] there were all kinds of strains, disagreements, and rivalries between the three men ... the electoral process sometimes got the better of them and someone quite different, not at all to their liking, was voted in".