The brothers Bridei son of Derelei (ca. 697– 706) and Necton son of Derelei (ca. 706/710– 724/732) were pivotal in the development of the Pictish kingdom. Their reigns coincide with a comparative increase in contemporary sources which has given historians the opportunity to develop various explanatory narratives of Pictish political progress. As a result, it is one of the most regularly re-envisioned historical periods. Before Bridei son of Derelei became king, however, he had to remove Taran son of Entifidich (ca. 693– 697). Just a year into Taran's reign the chronicles note the siege of Dunottar; this argues against unanimous support for his ascension. Exactly how or why Taran was ousted from office and sent into exile two years later is uncertain, although scholars have detected the hand of Iona in the manoeuvre. Parallels with Taran's fate and a story in the Life of St Columba were identified; particularly in its depiction of Taran, the exiled nobleman from Pictland who is given succour by Columba. What may link Adomnán more directly to this event is that, in the same year as Taran is deprived of kingship, Bridei son of Derelei is named guarantor to the abbot's famous Cáin Adomnáin (also known in Latin as lex innocentium— law of the innocents). A compensatory law protecting non-combatants (women, children, clerics, and churches), it was issued at the synod of Birr, Ireland in 697. Its signatories included kings and bishops of Ireland, Dál Riata, and Pictland. In the list of guarantors Bridei is styled rí Cruithintuathi (Old Irish— king of the Picts); a genitive singular construct that implies the king represented a single polity, not just a single province. The guarantor list also provides the first mention of a bishop of the Picts, one Curetán of Rosemarkie.

Despite their relative increase, sources in this period have proved confusing, with Bridei and Necton accorded different patronyms: sons of Dargart and/or sons of Derelei. It was assumed that this referred to four separate individuals, who happened to share similar first names. A 2004 article by Thomas Clancy offered a resolution to these discrepancies. By exploring a range of sources, he determined it likely that Bridei and Necton's father was Dairgart mac Finguine of the Cenél Comgaill (died ca. 686/693), from a branch of the Dál Riata.