A kingdom known from fragments
Fortriu is the best documented of the Pictish kingdoms, and also one of the most debated. It appears in Irish annals and in later king lists as the home of powerful kings, and its people, the Verturiones, are probably the “Verturiones” whom a fourth-century Roman writer mentions among the northern peoples. No Pictish chronicle survives, so the evidence is thin: Irish annals, Bede’s history, a few king lists compiled later, Adomnán’s life of Columba, and carved stones, including the Pictish symbol stones whose meaning is still debated.
The title calls this a “forgotten” kingdom. A more accurate description is that Fortriu was well known to its neighbours and then slowly dropped out of memory as the Pictish identity gave way to a Gaelic-speaking kingdom. Its disappearance from view is a matter of sources, not of its importance. Fortriu’s people had also faced Rome in some form, a background summarised under the Picts and Romans.
Where was Fortriu?
For a long time, historians placed Fortriu in the north, around Moray, partly on the basis of older readings of the sources. More recent work, resting on place-names, the distribution of carved stones and the Irish annals, tends to place it in central Scotland, in the area around the River Tay and Strathearn, with Perthshire as a likely core. This is a scholarly argument that has not ended, and it is sensible to say “probably” when discussing the location.
The kingdom’s size is also unclear. It may have been one of a number of regional Pictish kingdoms whose rulers sometimes claimed wider authority over others.
Bridei and the battle of Dunnichen
The best-known event in Fortriu’s history is the battle usually called Dunnichen, fought in 685. The Northumbrian king Ecgfrith, who had dominated much of Pictland for years, led an army north. The Pictish king Bridei son of Bili, who is linked to Fortriu in the sources, met and defeated him. Ecgfrith was killed. Bede describes the defeat as a turning point for Northumbria, and many later historians have agreed that it ended Northumbrian expansion northward.
The place of the battle is called Nechtansmere by Bede and Dun Nechtain in the Irish annals. A site at or near Dunnichen in Angus has been accepted by many scholars. A rival location near Loch Insh has also been argued, and the matter is not settled. The carved Pictish stone at Aberlemno, which shows a battle scene, is sometimes linked to this event, but that connection is debated, and the stone could depict another conflict.
Christianity
Christianity was already known in parts of Pictland before 685. Bede credits Ninian with converting southern Picts and Columba, from the Gaelic west, with the northern ones, though the dating of both is vague and historians prefer to speak of a gradual process involving missionaries and monasteries, mostly in the sixth to eighth centuries.
A well-attested milestone comes around 710, when King Nechtan, a Pictish ruler, wrote to the abbot of Jarrow in Northumbria asking for advice on keeping Easter on the Roman date and on church building. According to Bede, he then ordered the Pictish clergy to adopt the Roman Easter. This shows a Pictish king engaged with wider Christian debates, and it influenced relations with both Iona and Northumbria. Later Pictish stones, with crosses alongside the older symbols, show the blending of traditions. Iona, the island monastery connected with Columba, is also traditionally linked to the Book of Kells, although where that manuscript was made is debated.
The Fortriu kings and the eighth century
In the eighth century, kings associated with Fortriu appear to have been strong. Óengus son of Fergus, who reigned in the 730s and 740s, is said in the annals to have attacked the Gaelic kingdom of Dál Riata and to have exercised control over it. The Pictish dominance over the Gaels is a major reason that a later union of the two peoples under a Pictish-based king is not as unexpected as it may look. Later in the century, these kingdoms came under strain from internal disputes over the throne.
Vikings and the turning point of 839
From the end of the eighth century, Viking raiders attacked Scottish coasts and islands, including Iona. In 839, according to the Irish annals, a large battle with Vikings led to the deaths of a Pictish king and many leading men. A period of instability followed, and it is generally accepted that the old Pictish leadership was badly weakened.
Cinaed mac Ailpin and the union
By the 840s, Cinaed mac Ailpin (Kenneth MacAlpin) emerged as king of the Picts. Later medieval sources present him as the first king of Scotland and as someone of Gaelic descent from Dál Riata who took the Pictish throne, sometimes through a legendary massacre. Modern historians doubt the massacre story, and they see the change more as a political shift in a time of Viking pressure. Whether he came from a family of mixed Pictish and Gaelic background is uncertain.
The Pictish and Gaelic kingdoms then merged over time. By the end of the ninth century, the rulers were described as kings of Alba rather than of the Picts. The Pictish language and customs faded in the following generations, as Gaelic became dominant, but place-names, carved stones and some church traditions kept a trace of the older kingdom.
Why Fortriu matters
Fortriu offers a case study of how a medieval kingdom can be important yet poorly recorded. Its history, as far as we can read it, shows a capable and resilient state that defeated Northumbria, adapted to Christianity and eventually merged with its neighbours. It also shows how much of early Scotland’s story depends on reading short annals carefully and admitting where the evidence stops.