British kingship seems to have been a reaction to Germanic migration and settlement – the timing is right and the motivation makes sense. The historical fact is that the British had developed primitive kingships by the end of the century. If they had not, they might have all been speaking Anglo-Saxon in another hundred years.
There was much more to Celtic kingship than just a military leader who lived in a hall. A king not only had to be a good warrior and leader, he had to come from a long line of strong kings; which is why lineages often consisted of famous heroes of the area as well as the actual royal ancestors of a dynasty. The Irish law texts say he had to make consistently correct judgments in legal matters for his people. He could never turn his back in battle. He could not lie or tolerate bardic satire. His body could have no blemishes.
Kings had to be all these things because of their connections to the supernatural. A Celtic king did not just rule his kingdom; during his inauguration he literally married the land in the form of a woman, and legend had it that for the rest of his reign she would reflect his rule by her appearance. He married a young and beautiful woman because he had demonstrated to his clan and the people that he was the best candidate for the position. As long as he behaved like a king she would remain youthful and attractive, but if he ever lost his kingly virtue she would become an old hag until he was replaced with a worthy king.
This connection to the land as symbolized by a woman gave the king an authority beyond the question of normal humans, putting their kingship and by extension their clan above question as rulers in the eyes of peasants. When Celtic kingship developed, though, it had taken time to develop. Bards had gradually added people and stories, of actual ancestors and adopted ones, to each kingdom’s official history along the way. The mystical elements probably developed after dynasties were long established. As Vansina has demonstrated, anything beyond living memory can be easily changed and rechanged as local politics and events occur.
The Britons of the Post-Roman era did not have the luxury of time as they reestablished their original culture, though. The Germanic tribes began migrating onto and controlling villages from around 441. The result was that the British kingships that did emerge did not have the solid foundations necessary. It would not have mattered how good their bards were at creating impressive genealogies and personal histories for their first generation kings or reinvigorating the mystique behind kingship. The simple fact was that in the late fifth century people still remembered a time without kings.
And because kingship was such a new establishment for the Romano-Britons, fifth-century kingships would have been based almost solely on the personal chemistry between the chieftain and his men. When he died, or even when he lost too many battles, that chemistry could dissolve and any person who was able to generate a new bond might succeed him. A son, brother, or cousin might have succeeded him but that was only one of several possibilities. A nearby king might absorb the teulu or a former champion might assert himself. It may never be possible to list all the petty chieftainships that arose in the late fifth century, or the ways in which most of them disappeared from history.
On the other hand, the fact that none of the early kingships were stable is probably one of the main reasons why the early British kingdoms grew so quickly; without a strong tradition there would have been no kingdom identity among villages and therefore no resistance to changing kings. The unique situation of the fifth century would have allowed a ruler to simply absorb a chieftainless teulu just as easily as a victorious king could absorb his dead enemy’s villages.
1 Corpus Iuris Hibernici, ed. David A. Binchy, (Dublin, 1978), 219.17-18.
2 Ibid, 15.2-3.
3 O’Rahilly, “On the Origin of the Names Érain and Ériu”, Ériu 35 (Dublin, 1946b), 11-13.
4 Vansina, Oral Tradition as History, (Madison, 1985).