De bello Gallico

Commentarii de Bello Gallico
(Commentaries on the Gallic War)

First page of De bello Gallico, from a 1469 manuscript
Author	Julius Caesar, Aulus Hirtius (VIII)
Language	Classical Latin
Subject	History, Ethnography, Military history
Publisher	Julius Caesar
Publication date	58–49 BC
Followed by	Commentarii de Bello Civili

Commentarii de Bello Gallico (English: Commentaries on the Gallic War), also simply Bellum Gallicum (English: Gallic War), is Julius Caesar's firsthand account of the Gallic Wars, written as a third-person narrative. In it Caesar describes the battles and intrigues that took place in the nine years he spent fighting the Germanic peoples and Celtic peoples in Gaul that opposed Roman conquest.

The "Gaul" that Caesar refers to is sometimes all of Gaul except for the Roman province of Gallia Narbonensis (modern-day Provence), encompassing the rest of modern France, Belgium and some of Switzerland. On other occasions, he refers only to that territory inhabited by the Celtic peoples known to the Romans as Gauls, from the English Channel to Lugdunum (Lyon).

The work has been a mainstay in Latin instruction because of its simple, direct prose. It begins with the frequently quoted phrase "Gallia est omnis divisa in partes tres", meaning "Gaul is a whole divided into three parts". The full work is split into eight sections, Book 1 to Book 8, varying in size from approximately 5,000 to 15,000 words. Book 8 was written by Aulus Hirtius, after Caesar's death.

The Latin title, literally Commentaries on the Gallic War, is often retained in English translations of the book, and the title is also translated to About the Gallic War, Of the Gallic War, On the Gallic War, The Conquest of Gaul, and The Gallic War.

The victories in Gaul won by Caesar had increased the alarm and hostility of his enemies at Rome, and his aristocratic enemies, the boni, were spreading rumors about his intentions once he returned from Gaul. The boni intended to prosecute Caesar for abuse of his authority upon his return, when he would lay down his imperium. Such prosecution would not only see Caesar stripped of his wealth and citizenship, but also negate all of the laws he enacted during his term as Consul and his dispositions as pro-consul of Gaul. To defend himself against these threats, Caesar knew he needed the support of the plebeians, particularly the Tribunes of the Plebs, on whom he chiefly relied for help in carrying out his agenda. The Commentaries were an effort by Caesar to directly communicate with the plebeians - thereby circumventing the usual channels of communication that passed through the Senate - to propagandize his activities as efforts to increase the glory and influence of Rome. By winning the support of the people, Caesar sought to make himself unassailable from the boni. The work is a paradigm of proper reporting and stylistic clarity.