Constantín mac Cináeda

Causantín mac Cináeda
18th century depiction of Causantín, son of Kenneth MacAlpin. The depiction is highly anachronistic.
King of the Picts
Reign	862–877
Predecessor	Donald I
Successor	Áed
Died	877 Atholl?
Burial	Iona
Issue	Donald II, King of the Picts/of Alba
House	Alpin
Father	Kenneth I, King of the Picts

Causantín or Constantín mac Cináeda (in Modern Gaelic: Còiseam mac Choinnich; died 877) was a king of the Picts. He is often known as Constantine I in reference to his place in modern lists of kings of Scots, but contemporary sources described Causantín only as a Pictish king. A son of Cináed mac Ailpín ("Kenneth MacAlpin"), he succeeded his uncle Domnall mac Ailpín as Pictish king following the latter's death on 13 April 862. It is likely that Causantín's (Constantine I) reign witnessed increased activity by Vikings, based in Ireland, Northumbria and northern Britain. He died fighting one such invasion.

Very few records of ninth century events in northern Britain survive. The main local source from the period is the Chronicle of the Kings of Alba, a list of kings from Cináed mac Ailpín (died 858) to Cináed mac Maíl Coluim (died 995). The list survives in the Poppleton Manuscript, a thirteenth-century compilation. Originally simply a list of kings with reign lengths, the other details contained in the Poppleton Manuscript version were added from the tenth century onwards. In addition to this, later king lists survive. The earliest genealogical records of the descendants of Cináed mac Ailpín may date from the end of the tenth century, but their value lies more in their context, and the information they provide about the interests of those for whom they were compiled, than in the unreliable claims they contain. The Pictish king-lists originally ended with this Causantín, who was reckoned the seventieth and last king of the Picts.