|Retrieving an object from boiling water without|
suffering burns would prove innocence.
She was the daughter of King Eric IX of Sweden (d.1160) and was married to King Sverre of Norway (c.1151 - 1202) in 1189. Sverre fell ill and died on 9 March on his return from a military expedition. Margaret returned to Sweden after his funeral, but her daughter, Kristina, was not allowed to return with her. Sverre's successor (King Haakon III, a son from a previous marriage) kept Kristina at his court. This, presumably, caused some hostility between Margaret and Haakon.
Two years later, Margaret decided to return to Norway. Unfortunately for Margaret, Haakon died very shortly after her return, and accusations of poison were made against her.
Margaret invoked Trial by Ordeal* to prove her innocence, and had a man undergo the ritual in her place. Sadly, he was badly burned—not surprising to a modern audience, but proof of guilt to the law court of the time. The man was drowned, and Margaret had to flee for her life back to Sweden.
Haakon died without a son, so Guttorm (a grandson of Sverre) was named king, even though he was only four years old. No one was around to carry a grudge against Margaret, so in 1209 she returned to Norway for the wedding of Kristina to one of the regents for Guttorm. Sadly, she became ill and died a few weeks after the wedding.
*See the post on Trial by Combat.