A more thorough explanation:

Definition: In manu mortua is a legal term that means "in a dead hand." It refers to property that is perpetually controlled according to a decedent's directions.

For example, land held by a religious society was described this way because the church could hold property perpetually without rendering feudal service. This means that the property would remain under the control of the church even after the original owner had died.

Explanation: The term "in manu mortua" is used to describe property that is controlled by someone who has died. This can happen when the property is left to a religious organization or other group that is able to hold onto it indefinitely. The example of land held by a religious society illustrates this concept because it shows how the church was able to maintain control over the property even after the original owner had passed away.