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A Covenant (an agreement by deed) that prohibits the convenantee from doing something. Whether a covenant is restrictive or not is a question of form, not of substance (Tulk v moxhay (1832)), and is often assessed by determining whether it requires expenditure on the part of the covenantee. A restrictive covenant is always enforceable between the original parties, under straightforward common-law principles. The more interesting question is whether a restrictive covenant can be made to 'run with the land', that is, bind purchasers of the land who are not parties to the original covenant. See Covenant for more details.