The Trial Beneath The Light is a custom of the Whitecloaks, rarely used, which settles an accusation by trial of combat. It is used when one Whitecloak accuses another of a crime, such as abuse of a member of one's family. It was most often used when the accused knew they had a poor case, and would rather settle the matter with swords. The matter is supposed to be decided by the favour of the Light.

Before Galadedrid Damodred's successful challenge of Eamon Valda in KOD Prologue, where he was the accuser, the Trial had not been invoked for nearly four centuries.

The combatants remove their armour and cloaks before the combat, and meet for one final private exchange of words. If the matter is still not resolved, then they fight with swords until one of them is dead. No others may intervene on pain of death. The loser is stricken from the rolls and declared anathema.