Gallic Wars: Book VII

Book VII describes a year in the Gallic Wars (58-51 BCE) conducted by Julius Caesar against the Celtic Tribes in Gaul. After the War, Gaul became a Roman Province for the next 400 years.
Julius Caesar wrote De Bello Gallico using the third person to describe his personal experience as the Commander-in-chief.

In late 53 BCE Vercingetorix, arose as a new Leader. He had a new strategy which was to unite all the Gallic Tribes and persuade the Roman Client Tribes to change sides, avoid set Battles and harass the Romans, depriving them of supplies by burning all their villages, small towns, crops and stores.
He proposed to retire to hilltop fortresses where sieges would fail as the Romans wouldn’t be able to last without supplies.
The strategy almost worked. According to Frontinus, Caesar was warned of the Revolt of the Gauls under Vercingetorix during the winter of 53 BCE by Messenger Pigeon, and he immediately came back from Italy.
Caesar managed to finally outmanoeuvre Vercingetorix at the Battle of Alesia.