The common law principle that prohibits granting of an estate that will not vest within 21 years of that granting, that is, within 21 years of the death of the person who created the interest. Its purpose is to limit the amount of time that title to a property could be suspended and thereby keep the property from becoming available in the market. rule in Shelley's Case n. This rule governing property dates from 1324 and states that if a property is bequeathed to a person and a remainder to hi...