Alongside the Saxons, Scots, Irish, Franks and Attacotti the Picts played a key role in the barbarian conspiracy of 367 and continued their raids into the following century. In the early 400s, they posed a significant threat to the crumbling edifice of Roman Britain. Their attacks wreaked havoc among civilian communities in the lands south of Hadrian’s Wall, highlighting the feebleness of whatever remained of the imperial garrison. In the sixth century, a British cleric called Gildas looked back upon these woeful times and saw the Picts as a major cause of destruction and distress. He envisaged their seaborne attacks intensifying after 410, when Honorius suspended imperial rule in Britain:

As the Romans went back home, there emerged from the coracles that had carried them across the sea-valleys the foul hordes of Scots and Picts, like dark throngs of worms who wriggle out of narrow fissures in the rock when the sun is high and the weather grows warm.

Gildas believed that this new phase of raiding was briefly resisted by the Britons before resuming in earnest around the middle of the fifth century. By then, the northern and western barbarians – the Picts and Gaels – had inflicted so much disruption that the Britons felt obliged to hire Germanic mercenaries as protectors. Although Gildas saw this policy as sowing the seeds of an Anglo-Saxon takeover, he did not deny that its initial objective was achieved. The raiders were successfully repulsed and made no further appearance for many years. Gildas then turned his attention to the revolt of the Germanic mercenaries and to the bitter wars that followed. His account does not say what became of the Picts at the time of the Anglo-Saxon revolt, nor does he take up their story at a later point. Pictish history in the years 450 to 550 is extremely vague, with only a handful of sources offering any kind of useful information, but among the various chronicles, legends and folk-traditions is a long list of kings.

The Pictish king-list survives in several versions, each displaying slight differences but all apparently deriving from a tenth-century original. The chronological span of reign-lengths runs from a remote prehistoric period to the end of the Pictish kingdom in the ninth century. Legendary material pushes the line of kings back to Cruithne, an eponymous ancestor whose name is simply the Irish word for ‘Pict’. According to a ninth-century legend, Cruithne had seven sons, each of whom founded seven provinces or sub-kingdoms roughly encompassing the Pictish heartlands. The seven realms have frequently been matched to seven major earldoms of medieval Scotland, but the resulting ‘fit’ is not particularly neat and there is no ancient warrant for it. Leaving Cruithne and his sons aside, we see the king-list naming some sixty individuals, the last of whom reigned c.850. No king in the earliest or ‘prehistoric’ portion of the list can be securely identified as a real figure. The horizon of Pictish history, in terms of reliable information in the literary sources, lies therefore in the mid-sixth century. Prior to c.550 no information in the king-list can be confirmed by reference to other texts. This uncertainty means that any pre-550 king named in the list should be regarded as legendary until a case for his actual existence can be made. Only one of these early kings – the mysterious Wradech Uetla – seems to be mentioned in a source outside the list: he may be the Pictish ruler ‘Feradach’ who appears in Irish tradition as a contemporary of the fifth-century Munster king Conall Corc. Another possibly real figure from before 550 is Drust, son of Erp, whom the list assigns to the period of Saint Patrick’s mission to Ireland in the fifth century. The long chronology of the list implies that the entire Pictish nation was ruled by a paramount monarch or ‘overking’ from Roman times to the mid-ninth century. Most historians would now regard such a scenario with scepticism. A more plausible interpretation envisages two or more regional overkingships developing in the sixth century, these being contested by powerful families within each region.

A striking feature of the king-list is the rarity of patrilineal inheritance, a system of succession in which authority passes from father to son. Although each king’s patronym is given, in the form ‘X son of Y’, the fathers seem not to be succeeded by their sons until the final century of Pictish kingship. This is a feature of ‘matriliny’ or matrilineal succession, a method of inheritance practised in various parts of the world in various periods. When applied in royal contexts, it usually transfers a king’s authority to his nephew (‘son of the king’s sister’) or to his brother (‘son of the king’s mother’). According to Bede, who probably had contacts among the Pictish clergy, the Picts were unusual among the peoples of the British Isles in choosing their kings from the female royal line. He stated that they used this method only when the succession was in doubt. A brief glance at the king-list seems rather to suggest that matriliny was the rule rather than the exception: before the ninth century, no Pictish overking is shown being succeeded by his son. Some historians therefore believe that Bede was mistaken in believing that matrilineal succession was used only in special circumstances. They take the view that Pictish royal inheritance was regularly determined by matriliny, at least in so far as the election of overkings was concerned. Other historians disagree by suggesting that the system was conventional and patrilineal and that the king-list is a flawed document, or that it reflects an alternating or rotating overkingship which transferred power to a different family when the sovereign died. In this book the matrilineal hypothesis is tentatively supported, although the point is nowhere pressed too strongly.

Whatever their arrangements in matters of royal succession, the Picts were largely indistinguishable from their neighbours in most aspects of society and culture. They were one of several barbarian nations inhabiting the fringes of Late Roman and early medieval Britain. Like the Scots and North Britons they entered the sixth century under the rule of kings, some of whom claimed superiority over others. Beneath the kings stood a landowning aristocracy, itself perhaps graded according to wealth and lineage, which provided manpower for royal warbands. Of the latter there were perhaps a considerable number at any one time, each serving the king of a small kingdom. How far these kings and their retinues saw themselves as members of an abstract Pictish ‘nation’ is impossible to assess, but the king-list implies the existence of at least one large regional hegemony or overkingship by c.550. With dubious and incomplete information at our disposal we can do little more than suggest one overkingship in the North, between Orkney and the Grampian mountains, and a southern counterpart in Perthshire. At times, these two may have been ruled as a single realm by a very powerful monarch. At other times, each or both may have divided into smaller realms which were more or less independent. One feature which arguably bound all Pictish communities within a defined identity was their common language, a form of Brittonic. This was sufficiently distinct from the speech of the adjacent North Britons by c.500 to warrant the modern labels ‘Pictish’ or ‘Pictish-British’. Thereafter it may have become receptive to Gaelic influences.