abstract:The common law rule against perpetuities forbids some future interests (traditionally contingent remainders and executory interests) that may not vest within the time permitted; the rule "limit[s] the testator's power to earmark gifts for remote descendants". In essence, the rule prevents a person from putting qualifications and criteria in his/her will that will continue to control or affect the distribution of assets long after he or she has died, a concept often referred to as control by the "dead hand" or "mortmain".
To enable these trusts, most of the states allowing them had to get rid of an old common-law principle called the "rule againstperpetuities, " which allowed trusts to exist only for about 90 years.