Adda waswie oneien offan severalde sonssoannen born tofan [[Ida fan Bernicia|Ida]], thede firstearste rulerhearsker ofoer Bernicia, as waslykas hissyn successoropfolger [[Æthelric]].
Adda maykin havede beenbefelhawwer thefan BernicianBernysje commanderyn atde theslach battle offan [[Caer Greu]] west hawwe, wheredêr't thede BritishBritske kingskeningen [[Peredur]] anden Gwrgi offan [[Ebrauc]] werede killed.dea yn Therefûn ishawwe. someDe confusionboarnen herebinne becauseit oflykwols anet conflictiens betweenoer sourcesdit konflikt. TheDe [[Annales Cambriae]] statesizze thatdat thede BattleSlach offan Caer Greu tookyn place580 in 580wie. The evidence for Adda being the Bernician king in question is that the [[Welsh Triads]] identify that leader as [[Ida]]. Since the sources agree that Ida died in 559, it is assumed that the Triads have named Ida by mistake, and that Adda -- the only son with a name similar to Ida's -- was meant. However, the [[Historia Brittonum]] states that Adda only reigned for 8 years after Ida, in which case either the Bernician leader must have been one of Adda's successors, or else one of the sources has the dates confused. It is also possible that Ælle of Deira led the Angles at Caer Greu -- certainly, Ebrauc ceased to exist as a British kingdom after the battle, with Deira taking over its territory. Since, however, the surviving northern British kingdoms subsequently combined to launch a vigorous campaign directed against Bernicia rather than Deira, this suggests that Bernicia was the original combatant.
Nothing elseFierders is knownder forneat certain aboutoer Adda's life orreignbekend. The earliest authorities differ widely on the order and the regnal years of the Bernician kings between the death of Ida and the beginning of [[Æthelfrith fan Northumbria|Æthelfrith's]] rule in 592/593.
