It was about this time, circa 800 that the Vikings attacked Scotland and Ireland. In 836, Alpin, virtually the last of the Dalriadic Scottish kings, fell near Laicht Castle, on the ridge which separated Kyle from Galloway. A single man who lay in a thick wood overhanging the entrance of the ford of a river wait for him killed him after he had destroyed Galloway. Alpin, son of Eochaid the Venomous was riding among his people when he was killed.

The accession of the son of Alpin, Kenneth MacAlpin, to the kingdom of the Scots, marked the beginning of a new direction in Scottish history. In the middle of the ninth century the Pictish resistance crumbled. After Kenneth had ruled his father’s land for only a few years, the Vikings struck at the Picts and Scots in 839. This was described by the Irish annalists as a battle between the Gentiles and the men of Fortren. Fortren was the new name given to the combined kingdoms of the Scots and Picts. In the great slaughter Eoganan son of Oengus and many others were killed. The death of Uven or Eoganan son of Oengus, King of the Picts, led to the need for a new leader, a king capable of reuniting the shattered kingdom of the Picts and Scots. That man was to be Kenneth Mac Alpin. His succession apparently through his mother being a Pictish princess took place in 841 or 842. His right to the throne was apparently not readily admitted. No doubt Kenneth's sovereignty of Dalnada was regarded as an obstacle to his becoming A rd-righ Albainn just as there is a tendency to prevent the merging of two ancient noble families or houses. The Pictish nobles seem to have resisted his claim and it appears to have taken six years for Kenneth to gain rule over all of the Picts. At any rate, there seems to have followed a conference at Scone-which had become the sacred centre of Pictavia -where, at a banquet, or conclave, Kenneth apparently met the "Seven Earls" of Alba. Whatever they were going to do, Kenneth by what is vaguely termed "the treachery of Scone " had all seven murdered, and thereupon seems to have been inaugurated Ard-righ without further question. At any rate, Kenneth MacAlpin became king of the united Picts and Scots by A.D. 843, and was crowned at Scone not long after in the Pictish monastery on the ancient Stone of Destiny, which to the present day is the Coronation Stone for all the British monarchs.

Dal Riada under Kenneth MacAlpin, king of the Scots, claimed the throne of the Picts and absorbed all of Pictland, and the whole of Scotland north of the Forth and Clyde, establishing Alba, the first united kingdom in Scotland in 844. The territory ranged from modern Argyll and Bute to Caithness, across much of southern and central Scotland. Alba was one of the few areas in the British Isles to withstand the invasions of the Vikings. The ancient link with Ireland (from which the Celtic Scots had emerged) was broken as a cordon of Scandinavian settlements was established in the Western Isles and Ireland. With southern England also conquered by the Norsemen and Danes, Alba was left isolated.

He and his successors waged many wars against the English and the Norsemen who continually raided the coasts and threatened the independence of Scotland. The early capital of King Kenneth was Dunstaffnage, which was in Argyll. It was not long after his accession to the kingship of the untied Picts and Scots that the capital of the kingdom was moved to Scone, where the historic "Moot Hill" became from then forward the legal center of all Scotland, as it had previously been of Pictland. Kenneth MacAlpin ruled for 16 years, until his death in 858. At that time his brother, Donald, succeeded him. Kenneth Mac Alpin was the founder of the dynasty that ruled Scotland in unbroken succession for well over a thousand years.

In those days the clans constituted the real power and influence throughout the Eastern Highlands and lowlands of Scotland. In Fife and Morey were extensive lands and holdings of the clan Duff. This clan later came to be known as the Clan MacDuff and within it developed the Wemyss Clan in Fifeshire. The lands on the north shore of the Firth of Forth, in Fifeshire form the parish of Wemyss.