2. The three main rules at common law.

The law which regulates dispositions fettering the future alienation, devolution or enjoyment of property falls under three main heads.

The first is the rule which invalidates limitations and trusts that impose restrictions upon the future alienation of property, which extend beyond the period permitted by the rule next mentioned1. An example of such a limitation or trust is a gift of land to be retained and used for ever as a burial ground2. This first rule, prohibiting trusts of perpetual duration, is not the subject of this title and is dealt with elsewhere3.

The second main rule is that directed against