Dictionary of National Biography, 1885-1900/Indulphus
INDULPHUS (d. 962), king of Scotland or Alba, was the son of Constantine II [q. v.], and succeeded Malcolm, the son of Donald, in 954. In his reign Dunedin, the fort of the Anglian Edwin (the future Edinburgh), was evacuated by the English. This was the first step in the extension of the Celtic kingdom of Alba south of the Forth or Scots Water. Indulphus defeated in Buchan a fleet of the Norse vikings, called Sumarlidi because they made their expeditions in summer, and probably commanded by the sons of Eric Bloody-Axe. This is all the 'Pictish Chronicle' Records, but the 'Prophecy of St. Berchan' adds that Indulphus died, as his father had died, at St. Andrews, a statement which seems to imply that, like Constantine, he became a monk, and is inconsistent with the assertion of a later and less trustworthy chronicler that he was killed by the Norsemen at Invirculen. He is said to have expelled Fothaad, the bishop of Alba, perhaps because the bishop had deprived the Culdees of Lochleven of their island in that loch on condition of giving them food and clothing, and Indulphus was a supporter of the Culdees. Indulphus was succeeded by Duff [q.v.], the son of Malcolm.
[Pictish Chronicle; Registrum Prioratus S. Andreæ; Skene's Celtic Scotland, i. 365.]