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.
Anglo-Saxon settlement of Britain
The Chronica Gallica of 452 records for the year 441: "The British provinces, which to this time had suffered various defeats and misfortunes, are reduced to Saxon rule." The Chronicle was written some distance from Britain. There is uncertainty about precise dates for fifth-century events especially before 446. This, however, does not undermine the position of the Gallic Chronicles as a very important contemporary source, which suggests that Bede's later date for 'the arrival of the Saxons' was mistaken. In the Chronicle, Britain is grouped with four other Roman territories which came under 'Germanic' dominion around the same time, the list being intended as an explanation of the end of the Roman empire in the west. The four share a similar history, as they were all given into the "power of the barbarians" by Roman authority: three were deliberately settled with German federates and though the Vandals took Africa by force their dominion was confirmed by treaty.