By the Court,
Sutherland, J.The doctrine that a covenant of warranty runs with the land and enures to the benefit of the assignee of the covenantee, who may bring an action for the breach of it in his own name against the original covenantor, is not questioned or denied. The only doubt upon this point which was ever entertained in this court was, whether, when a covenantee conveys with warranty, his grantee, upon eviction, could sue the original warrantor, or whether his remedy was confined to his immediate covenant *184of indemnity. The latter opinion was expressed in Kane v. Banger, 14 Johns. R. 89; but the whole subject was fully reviewed and considered in Withy v. Mumford, 5 Cowen, 137, where the broad doctrine that the assignee may maintain an action against the original covenantor, whether the immediate conveyance to him was with or without warranty, was, upon a consideration and review of all the cases, fully established. Coke litt. 384, b., 385, a. 4 Cruise's Dig. 452, 3. Croke's Eliz. 503. Sheph. Touch. 198, tit. Warranty. 2 Mass. R. 460. Booth v. Starr, 1 Conn. R. N. S. 244.
If the covenant passes to the assignee with the land, it cannot be affected by the equities existing between the original parties any more than the legal title to the land itself. A covenant under seal cannot be discharged by a parol agreement before breach, Kay v. Waghorne, 1 Taunt. 427. The discharge must be by matter of as high a nature as that which creates the debt or duty, Preston v. Christmas, 2 Wils. 86. This is universally true where the action is founded upon, of grows exclusively out of the deed or covenant. Blake's case, 6 Coke, 43. Alden v. Blague, Cro. Jac. 99. In covenant, therefore, award with satisfaction before breach is bad, because the plea goes to the covenant itself; though after breach it may be good, for then it goes only in discharge of the damages, and not of the deed. Snow v. Frankleyn, Lutwyche, 108, in my ed. of 1708, cited in others as 1 Lutw. 358.
The principle that a written contract or instrument cannot be essentially varied by pared, seems also to be applicable to this case, and to exclude the defence. The covenant in the defendant’s deed, it is conceded, embraces in its terms the mortgage, under and by virtue of which the plaintiff has been evicted. The defence is either that at the time of executing and delivering the deed, it was understood and agreed between the parties that the covenants should not extend to that mortgage, or, that after the deed was executed and delivered, the grantee agreed that it should not embrace the mortgage, and quoad hoc discharged the covenant. In the first point of view, the objection to the defence is, that it is attempting to show that the real contract between, the parties was different from that expressed in the deed, which upon well settled prin*185■tiples cannot be clone ; and in the second point of view, the .objection is equally fatal, as has already been shown, that a Covenant before breach cannot be discharged by parol. This ■view of the case would seem to show that if the action had been brought by and for the benefit of the grantee himself instead of his assignee, the defence could .not be sustained at law; though there are some peculiarities in the case to which I have not particularly adverted, which, as between the original parties, might affect or vary its character. Butler's note, 332, to Coke Litt. 384. Even a formal technical release from the covenant by the covenantee after the assignment, and a breach in the hand of the assignee, would not discharge it Middlemore v. Goodate, Cro. Car. 503. The case must be brought within the principle of fraud, and the assignee must be affected with it, before a defence of the nature of this can be available, and perhaps .even then it is not available at law. In the language of one of the plaintiff’s points, to allow a secret agreement in opposition to the plain import of a covenant running with the land, to control and annul it in the hands of .a bona fide assignee, would be a fraud upon such assignee which the law will not tolerate. The pleas do not charge the plaintiff with any notice whatever of the secret agreement between the defendant and Sandford, nor with any actual notice of the existence of this encumbrance at the time of his purchase ; though, if such actual knowledge had existed, I do sot perceive that it can vary or affect the case.
Judgment for plaintiff on the demurrers,