Celtic warfare
The "Gallic Wars" were a series of military campaigns waged by the Roman proconsul Julius Caesar against Gallic tribes, lasting from 58 BC to 51 BC. The Romans would also raid Britannia and Germania, but these expeditions never developed into full-scale invasions. The Gallic Wars culminated in the decisive Battle of Alesia in 52 BC, in which a complete Roman victory resulted in the expansion of the Roman Republic over the whole of Gaul. The wars paved the way for Caesar to become the sole ruler of the Roman Republic.
Germania Inferior
The first confrontations between a Roman army and the peoples of Germania Inferior occurred during Julius Caesar's Gallic Wars. Caesar invaded the region in 57 BC and in the next three years annihilated several tribes, including the Eburones and the Menapii, whom Caesar called "Germanic" but who probably were Celtic or at least mixed Celtic-Germanic. Germanic influence (mainly through the Tungri) increased during Roman times, leading to the assimilation of all Celtic peoples in the area.