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.
Gallienus
Gallienus (; ; c. 218 – September 268), also known as Gallien, was Roman Emperor with his father Valerian from 22 October 253 to spring 260 and alone from spring 260 to September 268. He ruled during the Crisis of the Third Century that nearly caused the collapse of the empire. While he won a number of military victories, he was unable to prevent the secession of important provinces. His 15-year reign was the longest since the 19-year rule of Caracalla.