The kingdom of Dal Riada emerged sometime towards the end of the fourth century AD centred on the western coast of Scotland particularly the district of Argyll. From the reign of Fergus mac Erc to that of Domnall Brecc, Dal Raida also included Antrim in northern Ireland.
The tenth century document the Senchus fer n'Alban sets out much of the genealogical information we have regarding the kings of Dal Riada and in particular how the descendents of Fergus mac Erc are divided into the three kindreds of the Cenel Gabhrain, the Cenel Loairn and the Cenel Oengusa. The Cenel Gabhrain was the senior branch and provided all the rulers for the first two centuries.
Matters become confused towards the end of the seventh century when rival claimants from the Cenel Gabhrain and the Cenel Loairn seem to have engaged in a dynastic struggle; which is why there is sometimes two kings ruling at the same time. The end result was to allow the first Oengus son of Fergus of the Picts to move in and take over. The Picts and Scots spent the next century or so of vying for dominance, until the time of Kenneth mac Alpin who settled the question once and for all in favour of the Scots.
Dal Riada didn't disappear with Kenneth mac Alpin, it's just that he and the rulers after him began calling themselves Kings of Alba much as previous Pictish rulers called themselves Kings of Fortrenn. They just needed a new name for a new political entity.
The kings of Dal Riada
Cenel Gabhrain
Cenel Loairn
Cenel Gabhrain
Cenel Loairn
Cenel Gabhrain
Cenel Loairn
Ruled by Pictish Kings
Cenel Gabhrain
Unplaced rulers
Ruled by Pictish Kings
Unplaced rulers
Pieced togther from the A Biographical Dictionary of Dark Age Britain by Ann Williams, Alfred P. Smyth and D. P. Kirby (Seaby 1991)