A more thorough explanation:

A cold-water ordeal is a primitive form of trial where an accused person is subjected to a dangerous or painful physical test, and the result is considered a divine revelation of their guilt or innocence. The accused is trussed and lowered into a pond, and if they sink, the water is deemed to have 'received them' with God's blessing, and they are quickly fished out. This type of ordeal was commonly used in Europe until the 13th century, but only sporadically after 1215, when the Fourth Lateran Council forbade the clergy from participating in ordeals.

Another example of an ordeal is the ordeal of the morsel, where the person who was to make the proof was given a one-ounce piece of bread or cheese that a priest had solemnly charged to stick in the throat of the guilty. A person who choked was declared guilty, and a person who did not was declared innocent.

These examples illustrate how ordeals were used to determine guilt or innocence in a way that was believed to be divinely guided. They were often painful and dangerous, and the outcome was seen as a sign from God. However, as society progressed, these methods were deemed unreliable and were eventually phased out.