The Fianna (Na Fianna)

A warrior band outside the law of any king, and the tests you had to pass to join.

The Fianna were not an army. They were roving bands of young men who lived apart from the settled kingdoms, hunting and fighting for half the year and quartered on the people for the other half, owing allegiance to their own leader rather than to any king. Something like this existed in early Ireland as a real social arrangement for young men not yet in possession of land, which is part of why the stories about them have such a particular flavour.

In the literature they are Fionn mac Cumhaill's men, and getting in was difficult. The tests given in the tales are a mix of the physical and the literary, and that combination is the point. A candidate had to know the twelve books of poetry. He had to stand in a waist deep hole armed with a shield and a hazel stick while nine warriors cast spears at him, and take no wound. He had to be chased through a wood and not be caught, with his hair still braided at the end of it, without cracking a dry stick underfoot or disturbing a branch. He had to pull a thorn from his heel at a run without slowing.

No man could join who had not forgiven any debt owed to his family for his death, so that no feud could follow him into the band.

They end at the battle of Gabhair, where the Fianna break against the high king's forces and the old order goes with them. Oisín and Caoilte survive into Saint Patrick's century to describe it.