Origins of the Kingdom of Alba in the context of "Constantine II of Scotland"

Tanistry was a system of inheritance practised by the Gaelic nobilities of Ireland, the Isle of Man, and parts of modern Scotland. It was distinctive in having an elected heir known as the tanist (Irish: tánaiste; Scottish Gaelic: tànaiste; Manx: tanishtey). This system was used to select the Chiefs of the Name (head of a clan) and the rulers of the various Gaelic kingdoms in Ireland and in Scotland.

When the chief or king died they were immediately succeeded by the tanist, who had typically been elected years earlier. A new election was then held to select the next tanist. This differs from other systems of elective inheritance, in that an heir was elected in advance of a vacancy, not after the vacancy arose. Valid candidates for the election were restricted to male members of the title holder's sept (extended family); the exact eligibility criteria differed between Ireland and Scotland. The electorate was identical to the set of valid candidates i.e. potential heirs would select a tanist from among themselves.

Scotland was divided into a series of kingdoms in the Early Middle Ages, i.e. between the end of Roman authority in southern and central Britain from around 400 AD and the rise of the kingdom of Alba in 900 AD. Of these, the four most important to emerge were the Picts, the Gaels of Dál Riata, the Britons of Alt Clut, and the Anglian kingdom of Bernicia. After the arrival of the Vikings in the late 8th century, Scandinavian rulers and colonies were established on the islands and along parts of the coasts. In the 9th century, the House of Alpin combined the lands of the Scots and Picts to form a single kingdom which constituted the basis of the Kingdom of Scotland.

Scotland has an extensive coastline, vast areas of difficult terrain and poor agricultural land. In this period, more land became marginal due to climate change, resulting in relatively light human settlement, particularly in the interior and Highlands. Northern Britain lacked urban centres and settlements were based on farmsteads and around fortified positions such as brochs, with mixed farming primarily based on self-sufficiency. In this period, changes in settlement and colonisation meant that the Pictish and Brythonic languages began to be subsumed by Gaelic, Scots, and, at the end of the period, by Old Norse. Life expectancy was relatively low, leading to a young population, with a ruling aristocracy, freemen, and relatively large numbers of slaves. Kingship was multi-layered, with different kings surrounded by their warbands that made up the most important elements of armed forces, and who engaged in both low-level raiding and occasional longer-range, major campaigns.

Tanistry was a system of inheritance practised by the Gaelic nobilities of Ireland, the Isle of Man, and parts of modern Scotland. It was distinctive in having an elected heir known as the tanist (Irish: tánaiste; Scottish Gaelic: tànaiste; Manx: tanishtey). This system was used to select the Chiefs of the Name (head of a clan) and the rulers of the various Gaelic kingdoms in Ireland and in Scotland.

When the chief or king died they were immediately succeeded by the tanist, who had typically been elected years earlier. A new election was then held to select the next tanist. This differs from other systems of elective inheritance, in that an heir was elected in advance of a vacancy, not after the vacancy arose. Valid candidates for the election were restricted to male members of the title holder's sept (extended family); the exact eligibility criteria differed between Ireland and Scotland. The electorate was identical to the set of valid candidates i.e. potential heirs would select a tanist from amongst themselves.