A more thorough explanation:

Regula Catoniana

Regula Catoniana is a principle in Roman law that means if something was void from the beginning, the passage of time cannot make it valid. It is named after the Roman legal scholar Cato. For example, if someone made a will when they were not of sound mind, the will would be considered void from the beginning, and the passage of time would not make it valid.

One example of Regula Catoniana is when a person makes a will but is not of sound mind. If the will is contested, the court may apply Regula Catoniana to set aside the bequest because the testator did not have the capacity to make the bequest.