What is “ordeal by water” in medieval justice?

The story behind the answer

In medieval law, ordeals were perilous tests meant to reveal divine judgment. The water version bound the accused and lowered them into a blessed pond or moat: floating signaled guilt because pure water was thought to reject sin; sinking implied innocence, and officials were expected to pull the person out rather than let them drown. A hot-water variant required retrieving a stone from boiling water, with the healing of burns judged days later.

Clergy often supervised until the Fourth Lateran Council (1215) forbade their participation, hastening the shift toward jury trials. Contrary to popular belief, this was not intended as an execution method. The later “witch-swimming” tests of the early modern period borrowed the same logic but were a separate phenomenon.