THE common law of perpetuities is one of the most interesting examples of almost pure judicial legislation. De Donis, The Statutes of Uses and of Wills, but gave wider scope to the development by the courts of rules of law to thwart the attempt of the great landowners to tie up their landed estates in their families in perpetuity. One body of rules to this end limited restraints upon alienation, another the creation of future interests vesting at too remote a period. Restriction of restraints upon alienation, and the rule against perpetuities, these two were developed for the same end, have been often confused, but are separate and distinct remedies. The rule against perpetuities seeks its end by forbidding the postponement of the vesting of future interests beyond the period of a life or lives in being and twenty-one years and nine or ten months. The other rule forbids restraints upon the absolute power to convey realty, and of the absolute ownership of personalty, beyond a like period. Only in recent times have the two been clearly distinguished by the courts.
Goddard, Edwin C. "Perpetuity Statutes." Mich. L. Rev. 22 (1923): 95-106.