Property law-Future use control-Rule against perpetuities + Doctrine of worthier title + Restraint on alienation + Rule in Shelley's Case

The rule against perpetuities is a legal rule in the Anglo-American common law that prevents people from using legal instruments (usually a deed or a will) to exert control over the ownership of private property for a time long beyond the lives of people living at the time the instrument was written. Specifically, the rule forbids a person from creating future interests (traditionally contingent remainders and executory interests) in property that would vest beyond 21 years after the lifetimes of those living at the time of creation of the interest, often expressed as a “life in being plus twenty-one years”. In essence, the rule prevents a person from putting qualifications and criteria in a deed or a will that would continue to affect the ownership of property long after he or she has died, a concept often referred to as control by the "dead hand" or "mortmain".

The basic elements of the rule against perpetuities originated in England in the 17th century and were "crystallized" into a single rule in the 19th century. The rule's classic formulation was given in 1886 by the American legal scholar John Chipman Gray:

No interest is good unless it must vest, if at all, not later than twenty-one years after some life in being at the creation of the interest.

— John Chipman Gray, Rule Against Perpetuities § 201.

In the common law of England, the doctrine of worthier title was a legal doctrine that preferred taking title to real estate by descent over taking title by devise or by purchase. It essentially provides that a remainder cannot be created in the grantor's heirs, at least not by those words.

The rule provided that where a testator undertook to convey an heir the same estate in land that the heir would take under the laws of inheritance, the heir would be adjudged to have taken title to the land by inheritance rather than by the conveyance, because descent through the bloodline was held to be "worthier" than a conveyance through a legal instrument.

A restraint on alienation, in the law of real property, is a clause used in the conveyance of real property that seeks to prohibit the recipient from selling or otherwise transferring his interest in the property. Under the common law such restraints are void as against the public policy of allowing landowners to freely dispose of their property. Perhaps the ultimate restraint on alienation was the fee tail, a form of ownership which required that property be passed down in the same family from generation to generation, which has also been widely abolished.

The Rule in Shelley's Case is a rule of law that may apply to certain future interests in real property and trusts created in common law jurisdictions. It was applied as early as 1366 in The Provost of Beverly's Case but in its present form is derived from Shelley's Case (1581), in which counsel stated the rule as follows:

…when the ancestor by any gift or conveyance takes an estate of freehold, and in the same gift or conveyance an estate is limited either mediately or immediately to his heirs in fee simple or in fee tail; that always in such cases, 'the heirs' are words of limitation of the estate, not words of purchase.