An account of the tumultuous situation in…

An account of the tumultuous situation in Britain between 364 and 369 is provided by the historian Ammianus, who describes a corrupt and treasonous administration, native British troops (the Areani) in collaboration with the barbarians, and a Roman military whose troops had deserted and joined in the general banditry.

The situation is a consequence of the failed imperial power-grab by Magnentius a decade earlier, followed by the bloody and arbitrary purge conducted by Paulus Catena in an attempt to root out potential sympathizers of Magnentius in Britain, and aggravated by the political machinations of the Roman administrator Valentinus.

Ammianus describes the marauders—Atacotti, Scotti, Picts, Saxons, Roman military deserters, and the indigenous Britons themselves—as bands moving from place to place in search of loot.