From Charles Squire's Celtic_Myth_and_Legend,
about qualifying to become a member of the Fenians
(an analog of Britain's knights):

It was not easy to become a member of this famous band.  A candidate
had to be not only an expert warrior, but a poet and a man of culture
as well.  He had practically to renounce his tribe; at any rate he made
oath that he would neither avenge any of his relatives nor be avenged
by them.  He put himself under bonds never to refuse hopsitality to
anyone who asked, never to turn his back in battle, never to insult
any woman, and not to accept a dowry with his wife.  In addition to
all this, he had to pass successfully thorough the most stringent of
physical tests. ...  An aspirant to the Fianna Eirinn, we are told,
had first to stand up to his knees in a pit dug for him, his only arms
being his shield and a hazel wand, while nine warriors, each with a
spear, standing within the distance of nine ridges of land, all hurled
their weapons at him at once; if he failed to ward them all off, he
was rejected.  Should he succeed in this first test, he was given the
distance of one tree-length's start, and chased through a forest by
armed men; if any of them came up to him and wounded him, he could not
belong to the Fenians.  If he escaped unhurt, but had unloosed a
single lock of his braided hair, or had broken a single branch in his
flight, or if, at the end of his run, his weapons trembled in his
hands, he was refused.  ... Besides these tests, he was obliged to
jump over a branch as high as his forehead, and stoop under one as low
as his knee, while running at full speed, and to pluck a thorn out of
his heel without hindrance to his flight....