Great Barbarian Conspiracy

Type: Event

As of November 2026, Great Barbarian Conspiracy has been mentioned in one podcast episode on History With Hilbert (Oct 2025). A coordinated attack on Roman Britain by multiple groups, including the Picts.

The Great Conspiracy was a year-long state of war and disorder that occurred near the end of Roman rule in Britain. Fourth-century Roman historian Ammianus Marcellinus describes it as a barbarica conspiratio which took advantage of a depleted military force in the province; many soldiers had marched with Magnentius in his unsuccessful bid to become emperor. Few returned, and supply, pay, and discipline in the following years may have been deficient.