The wars between the Picts and Northumbrians were succeeded by various contests for power among the Pictish princes, which gave rise to a civil war. Ungus, honoured by the Irish Annalists with the title of great, and Elpin, at the head of their respective partisans, tried their strength at Monacrib, supposed by some to be Moncrieff in Strathearn, in the year 727, when the latter was defeated; and the conflict was renewed at Duncrei (Crieff), when victory declared a second time against Elpin, who was obliged to flee from the hostility of Ungus. Nechtan next tried his strength with Ungus, in 728, at a place called Monacurna by the Annalists--possibly Moncur in the Carse of Gowrie--but he was defeated, and many of his followers perished. Talorgan, the son of Congus, was defeated by Brude, the son of Ungus, in 730, and in the same year the Picts appear to have entered into a treaty of peace with the English nation.
The victorious Ungus commenced hostilities against the Dalriads, or Scoto-Irish, in the year 736, and appears to have got the better of the latter. The Scots were again worsted in another battle in 740 by Ungus, who in the same year repulsed an attack of the Northumbrians under Eadbert. In the year 750 he defeated the Britons of the Cumbrian kingdom in the battle of Cato or Cath-O, in which his brother Talorgan was killed. Ungus, who appears to have been a powerful and able monarch, but whom Bede[95] characterizes as having conducted himself “with bloody wickedness, a tyrant and an executioner,” died about 760. A doubtful victory was gained by Ciniod, or Kenneth, the Pictish king, over Aodh-fin, the Scottish king, in 767. Constantine, having overcome Conall, the son of Tarla, in 789, succeeded him in the throne.[96]
Up to this period the Norsemen from Scandinavia, or the _Vikingr_, _i.e._ men of the voes or bays, as they were termed, had confined their ravages to the Baltic; but, in the year 787 they for the first time appeared on the east coast of England. Some years afterwards they found their way to the Caledonian shores, and in 795 made their first attack on Iona, which frequently afterwards, along with the rest of the Hebrides, suffered grievously from their ravages. In 839 the _Vikingr_ entered the Pictish territories. A murderous conflict ensued between them and the Picts under Uen their king, in which both he and his only brother Bran, as well as many of the Pictish chiefs, fell. This event, no doubt, hastened the downfall of the Pictish monarchy; and as the Picts were unable to resist the arms of Kenneth, the Scottish king, he carried into execution, in the year 843, a project he had long entertained, of uniting the Scots and Picts, and placing both crowns on his head. That anything like a total extermination of the Picts took place is now generally discredited, although doubtless there was great slaughter both of princes and people. Skene[97] asserts indeed that it was only the Southern Picts who became subject to Kenneth, the Northern Picts remaining for long afterwards independent of, but sometimes in alliance with, the Scots. This is substantially the opinion of Mr. E. W. Robertson,[98] who says, “the modern shires of Perth, Fife, Stirling, and Dumbarton, with the greater part of the county of Argyle, may be said to have formed the actual Scottish kingdom to which Kenneth succeeded.” The Picts were recognised as a distinct people even in the tenth century, but before the twelfth they lost their characteristic nominal distinction by being amalgamated with the Scots, their conquerors.