This question involves a bit of recent literature, but bear with me, it will get historical in a sec.

For those who do not know it, Bernard Cornwell's Warlord Chronicles tells a completly fictional tale, one of Arthur, Merlin, Guinivere etc. However, the historical context is fairly realistc, set in Dark Age Britain, during the Saxon invasions.

In the beggining of the first book of the trilogy, Arthur holds a trial in his Romano-Welsh kingdom of Dummonia. The trial can happen in the court of words, wich has a system of what types of testimony are accepted, wich in this case would disfavor Arthur. These are the Tongued Ones, and are discussed in this Ask Historians post: https://www.reddit.com/r/AskHistorians/comments/5t6w3u/is_there_any_historical_basis_for_the_tongued/

As you can see, this system presented in the book actually has a historical basis, and so comes the question itself. Does the second system, the one that Arthur choses, the court of swords, or as Game of Thrones would call it, trial by combat, have any historical basis in Welsh-roman medieval society?

It is depicted as a challenging of a lords word, in wich the acuser thrusts his sword into the dirt, and if the other lord knocks it over should he challenge the acusation, he accepts the trial, wich must take place outdors. It is a fight to the death.

Previously I fought that these trials by combat in fantasy (Warlord is not fantasy but you get my point) was only a way of making a trial something dinamyc and that shows a characters prowess in battle. But if the tongued ones system is true, then maybe the good historians in this subreddit can shed light if this sort of practice is accurate.

Thank you in advance.