Kenneth MacAlpin unites the Scots and Picts to form a kingdom in central Scotland, ruling as Kenneth I. Kenneth's origins are uncertain, as are his ties, if any, to previous kings of the Picts or Dál Riata.

Compared with the many questions on his origins, Kenneth's ascent to power and subsequent reign can be dealt with simply.

Kenneth's rise can be placed in the context of the recent end of the previous dynasty, which had dominated Fortriu for two or four generations.

This followed the death in 839 of king Uen son of Óengus of Fortriu, his brother Bran, Áed mac Boanta "and others almost innumerable" in battle against the Vikings.

The resulting succession crisis seems, if the Pictish Chronicle king-lists have any validity, to have resulted in at least four would-be kings warring for supreme power.

Kenneth's reign is dated from 843, but it is probably not until 848 that he defeated the last of his rivals for power.