(The only plastic art work I know depicting this Trial is a fresco in Castelseprio, although it was a common theme among misteries, theater and to some extent literature pieces, for example the N-town Pageant series, a 15th century English manuscript.)
A variation of this trial emerged in the Middle Ages: the Trial by water. Women under witchery suspicion were trown to the water, because there was the belief that witches could float. If it occured the woman to float, then she was found guilty and executed. If she were innocent, she would very sadly die by drowning.
When the Hanseatic League waned, Riga became the aim of many religious aspirations. The Reformation succeed in 1522. Two years later, a popular and venerated statue of Mary was denounced as a witch, so she underwent the Trial of water. As the statue floated on the river Daugava, perhaps because it was made of wood, she was found guilty. So she was taken out and burned in Kubsberg.