The Catalyst of 455: A Pan-Insular Chronological Reconstruction of the British-Saxon Conflict

This paper reconstructs the sequence of events between 455 and 461 AD by resolving the systemic fragmentation of early medieval British and Irish historical sources. Utilising the Synonymous Name Method (SNM) framework, it identifies the British "Battle of the Long Knives" and the Irish "Feast at Tara" as a single, synchronised geopolitical catalyst. This flashpoint triggered a rapid, six-year chain of retaliatory engagements that culminated in a pan-Insular uprising and the Siege of Badon Hill in 461 AD. Furthermore, a structural textual analysis of the Historia Brittonum reveals that the four Kentish battles of Vortimer and the four regional battles of Arthur at the River Dubglas are localised duplicates of this exact same 455-461 AD campaign. This chronological compression demonstrates that the fall of the old Romano-British leadership (Ambrosius/ Palladius and Vortimer/Loeguire) occurred simultaneously in 461 AD, immediately clearing the geopolitical stage for the historical emergence of the next generation: Arthur (as the Continental warlord Riothamus) and Saint Patrick (as the historical Bishop Mansuetus).