The dynasty of Kenneth MacAlpin, which united the Picts and Scots into the kingdom of Alba and ruled it for nearly two centuries.
The dynasty is named for Kenneth MacAlpin (Cináed mac Ailpín), who around 843 became king of both the Picts and the Gaelic Scots of Dál Riata. Later tradition made him the conqueror who fused the two peoples; modern historians see a longer, murkier process of Gaelic ascendancy over a Pictish kingdom battered by Viking raids. Whatever the mechanism, from his reign the combined realm came to be called Alba, and its kings were drawn from his descendants.
The early kingdom was centred on the fertile lands of Fortriu and the Tay, with its royal and religious heart at Scone and Dunkeld, where relics of Columba were brought for safety from the Vikings.
The dynasty’s greatest figure was Constantine II, who reigned for over forty years from 900. He beat back Viking attacks, presided in 906 at Scone over a council that bound king and church together in the emerging Scottish kingdom, and manoeuvred among the rising powers of the Norse of Dublin and the English of Wessex.
In 937 he joined Olaf Guthfrithson and the Britons of Strathclyde in a great invasion of England, but was defeated by Æthelstan at the Battle of Brunanburh, where his son was killed. Late in life he abdicated to become a monk at St Andrews, a rare peaceful end for a king of the age.
For a century the crown passed among the branches of the house, often violently, by a system of alternating succession that pitted cousins against one another. The last king of the direct male line was Malcolm II, who strengthened the kingdom’s hold on the south and, lacking a son, arranged the succession of his grandson Duncan.
With Malcolm’s death in 1034 the crown passed to the related House of Dunkeld, but the kingdom of Alba that the house of Alpin had forged — the nucleus of medieval Scotland — endured and grew.