Trial by fire is one of the trials by ordeals that existed in medieval times across Europe. Other ordeals included trials by water, ingestion and by cross. These are related to trial by combat, where the accused fights the accuser. In trials by fire, the accused performs the trial without aid.
In English common law and the laws of many kingdoms across medieval Europe, trial by ordeal was used for invisible acts. If an act was witnessed, then the prosecution and the defense can call upon witnesses to give testimony. From that, judges and/or jurors are able to make a decision concerning the accused’s guilt. When an act lacked witnesses, they turned to God for assistance; if the accused was innocent, they believed God would aid them in a trial of some kind.
A trial by fire did not involve any naked flames. Instead, iron was heated up. One method involved the accused holding a red hot iron rod while walking 9 feet (2.74 m). The other, more common, method was for the accused to walk over red-hot iron ploughshares. Trial by water often required flames in order to boil barrels of water, oil or lead so the accused could pluck a rock from the bottom of the pot.
If the accused managed to complete the task, he would be bandaged up and given three days grace. Judges in these matters believed that God would intervene to perform a miracle on behalf of the innocent while leaving the guilty to fester. After three days, they would check the wounds for any sign of infection. If the wound was infected, the accused was deemed guilty; if not, he was found innocent.
A famous case of trial by fire involves Emma of Normandy in mid-11th century England. Emma had been wife to Aethelred the Unready and then Canute. She was also mother to the then King, Edward the Confessor. According to accounts and the legends that sprung up around them, she, then twice widowed, was accused of adultery with the Bishop of Winchester.
In order to prove the Bishop’s innocence, she submitted herself to trial by fire. Edward consulted his Norman priests and agreed, stipulating that she would have to walk across nine red-hot ploughshares. On the day of the trial, she strode across the court to ask the judges when the ordeal would take place. They then told her she had already passed, so she turned and saw the ploughshares behind her.
Pope Innocent III banned priests from attending any trial by fire or other trials by ordeal during the fourth Lateran council in 1215. As the medieval period wore on, such trials became less frequent. They eventually died out.