The Scottish monarchy of this period bases its succession system on the rule of tanistry.

All adult male descendants of previous monarchs are eligible for the throne.

The kingship regularly switches from one line of royal descendants to another, though they are all closely related.

The succession rule has the benefit of ensuring that there will always be an adult king on the throne, avoiding the usual problems of minority reigns.

The various kings have their lands and power bases in different areas of Scotland, preventing any single region from claiming full domination of the others.

This may have helped the country avoid significant secession movements.

The downside is that any single king has to face adult rivals for the throne.

His kinsmen have their own ambitions and will not wait for his death from natural causes to achieve them.

The succession is often decided through acts of warfare and murder, resulting in early deaths and high casualty rates in the extended royal family.

During the tenth century, there have been dynastic conflicts in Scotland between two rival lines of royalty.

One descends from Causantín mac Cináeda (Constantine I, reigned 862-877), the other from his brother Áed mac Cináeda (reigned 877-878).

Constantine III belongs to the second line.

His royal ancestors include Áed himself, Constantine II of Scotland (reigned 900-943), Indulf (reigned 954-962), and Cuilén (reigned 967-971).

Amlaíb of Scotland (reigned 973-977) was his paternal uncle.

The alternation between the two royal lines seems to have been peaceful for a long time; Alfred P. Smyth regards this early phase as "a century of kingly coexistence".

The armed conflict between the lines seems to have started in the 960s, when Cuilén challenged the rule of his cousin Dub, King of Scotland (962-967).

The initial motivation behind the conflict is unclear.

Smyth speculates that control over the Kingdom of Strathclyde might have been a major factor.

According to John of Fordun (fourteenth century), Kenneth II (Cináed mac Maíl Coluim), King of the Scots,(reigned 971-995) attempted to change the succession rules, allowing "the nearest survivor in blood to the deceased king to succeed", thus securing the throne for his own descendants.

He reportedly did so to specifically exclude Constantine (III) and Kenneth (III), called Gryme in this source.

The two men then jointly conspired against him, persuading Finnguala, daughter of Cuncar, Mormaer of Angus, to kill the king.

She reportedly did so to achieve personal revenge, as Kenneth II had killed her own son.

Entries in the Chronicles of the Picts and Scots, collected by William Forbes Skene, provide the account of Finnguala killing Kenneth II in revenge, but not her affiliation to Constantine or his cousins.

These entries date to the twelfth and thirteenth centuries.

Kenneth II is killed in 995, the Annals of Ulster say "by deceit" and the Annals of Tigernach say "by his subjects".

Some later sources, such as the Chronicle of Melrose, John of Fordun and Andrew of Wyntoun provide more details, accurately or not.

The simplest account is that he was killed by his own men in Fettercairn, through the treachery of Finnguala (also called Fimberhele), daughter of Cuncar, Mormaer of Angus, in revenge for the killing of her only son.

Constantine, son of Cuilén, who is associated with this in several accounts, becomes king, known in most modern regnal lists as Constantine III.

John of Fordun, perhaps confusing him with Eógan II of Strathclyde, known as "the Bald", refers to Constantine as "the Bald".

Constantine had been able to rise to the throne, despite his cousin and predecessor having a son of his own.

The next two kings (Kenneth III, Malcolm II) are his cousins, and will kill their respective predecessor to gain the throne.