In Appian’s Roman History—especially the section known as the Civil Wars—the rise of the Second Triumvirate is portrayed as a decisive and violent turning point in the collapse of the Roman Republic. Appian details how Octavian (Augustus), Mark Antony, and Marcus Lepidus formed the legally sanctioned alliance in 43 BCE through the Lex Titia, granting themselves extraordinary powers to restore order after the assassination of Julius Caesar. His account emphasizes the ruthless proscriptions, political purges, and property confiscations that funded their armies and eliminated rivals such as Cicero. Appian presents the Triumvirs’ victory over Brutus and Cassius at the Battle of Philippi (42 BCE) as the effective end of Republican resistance, while also highlighting the fragile unity that ultimately dissolved into renewed civil war between Octavian and Antony. As a crucial primary source on the Roman civil wars, Appian’s narrative provides invaluable insight into the political violence, shifting alliances, and constitutional breakdown that paved the way for the rise of the Roman Empire.

In Cassius Dio’s Roman History, the formation and rule of the Second Triumvirate (43 BCE)—composed of Octavian, Mark Antony, and Lepidus—is portrayed as a calculated but ruthless power-sharing agreement that accelerated the collapse of the Roman Republic. Writing in the early third century CE, Cassius Dio provides one of the most detailed surviving narratives of the triumvirs’ proscriptions, political maneuvering, and military campaigns, including the defeat of Brutus and Cassius at the Battle of Philippi (42 BCE). Dio emphasizes the brutality of the proscriptions, highlighting the execution of Cicero as a symbol of the Republic’s destruction, while also analyzing the shifting alliances that ultimately led to conflict between Octavian and Antony. His account frames the Second Triumvirate not merely as a temporary magistracy, but as a decisive step toward the establishment of the Roman Empire under Augustus, making Dio’s narrative an essential source for understanding the violent transition from Republic to Principate.

Plutarch, the Greek biographer and author of the Parallel Lives, provides one of the most influential ancient accounts of the Second Triumvirate, the political alliance formed in 43 BCE between Octavian (Augustus), Mark Antony, and Lepidus after the assassination of Julius Caesar. In his biographies of Antony and Brutus, Plutarch offers detailed narratives of the proscriptions, the ruthless elimination of political enemies, and the escalating power struggle that reshaped the Roman Republic. His portrayal emphasizes the moral character and personal ambitions of the triumvirs, particularly highlighting Antony’s relationship with Cleopatra VII and its impact on Roman politics. Through vivid storytelling and ethical analysis, Plutarch’s account of the Second Triumvirate remains a crucial primary source for understanding the collapse of the Republic and the rise of the Roman Empire under Augustus.

The Letters of Cicero provide a crucial primary source for understanding the political chaos surrounding the rise of the Second Triumvirate (43 BCE), formed by Octavian (Augustus), Mark Antony, and Lepidus. In his correspondence—especially the Letters to Atticus and Letters to Friends (Ad Familiares)—Cicero reveals his fears about the collapse of the Roman Republic, his opposition to Mark Antony, and his cautious initial support for Octavian as a potential defender of senatorial authority. The letters expose the escalating tensions following the assassination of Julius Caesar, the power struggles in Rome, and the atmosphere of suspicion that led to the infamous proscriptions of 43 BCE, during which Cicero himself was targeted and executed. As firsthand political commentary, Cicero’s correspondence offers invaluable insight into the ideological conflict between republicanism and emerging autocratic rule, making it an essential source for scholars studying the fall of the Republic and the consolidation of power under the Second Triumvirate.

In Roman History by Velleius Paterculus, the formation of the Second Triumvirate (43 BCE) is portrayed as a decisive yet turbulent moment in late Roman Republic history, marking the alliance of Octavian (Augustus), Mark Antony, and Lepidus following the assassination of Julius Caesar. Writing under the reign of Tiberius, Velleius Paterculus offers a perspective that is notably sympathetic to Octavian, emphasizing his political skill and legitimacy while framing the triumviral proscriptions, including the execution of Cicero, as harsh but consequential measures in restoring order. The historian presents the Battle of Philippi (42 BCE)—where the forces of the triumvirs defeated Brutus and Cassius—as a pivotal step toward stability and the eventual rise of the Roman Empire. As a primary source for the Second Triumvirate, Velleius’ account is invaluable for understanding both the political propaganda of the early empire and the transformation from Republic to Principate in Roman history.