— The charge given in this case can not be correct, unless the payment of the money, advanced by the appellant for the intestate of the appellee, would, at law, divest and transfer to the latter the title vested in the former by the conveyance to him. Jones, at the request of Trawick, advanced the purchase-money of a slave bought by the latter; and, at the request of Trawick, a *256written conveyance of tlie slave was made to Jones by the vendor, for the security of the repayment of the purchase-money advanced by Jones. Jones’ title, thus derived, could not be divested by the payment of the money advanced by him, unless a condition could be incorporated upon the bill of sale by proof of a cotemporaneons or antecedent parol agreement, in a suit at law; thus giving it the effect of a mortgage. It is now well settled, that an absolute conveyance may, in a court of equity, be shown to have been designed to operate as a mortgage; and will, upon proper proof, be treated as a mortgage in that court. But the chancery court, in treating an absolute conveyance as a mortgage, proceeds upon principles peculiar to itself. The jurisdiction of the chancery court to declare an absolute conveyance a mortgage, has often been assailed, as an infringement of the wholesome rule that a written contract can not be varied by parol evidence. It has been maintained, however, upon the ground that the court may, for the purpose of preventing the fraudulent use of a conveyance, interpose and enforce the parol trust upon which it was made. — Bishop v. Bishop, 13 Ala. 475; Kennedy v. Kennedy, 2 Ala. 571; Sledge v. Clopton, 6 Ala. 589; Parish v. Gates, 29 Ala. 254; Edmundson v. Welsh and Wife, 28 Ala. 578.
The jurisdiction of the court of equity rests upon grounds not recognized in a court of law. We have in this State no case, in which a court of law has assumed to enforce the parol trusts upon which a written conveyance was made; and there is no principle upon which the exercise of such power by a court of law can be upheld. The rule, that the written contract cannot be varied by parol evidence, is unbending at law; and the exceptions which prevail in a court of chancery are referrible to its peculiar jurisdiction over trusts, and for the prevention of frauds.
In the ease of Sewall v. Henry, 9 Ala. 24, there was a eotemporaneous written instrument, which was construed to be a part of the same instrument with, and to provide a condition to the conveyance. In the old case of Harrison & Harrison v. Hicks, 1 Porter, 428, the conveyance was modified and altered into a mortgage, or pledge, by a *257subsequent parol agrément. That case is maintainable, upon the principle that a written contract may be altered by a posterior parol agreement; and does not violate the rule, which prohibits the variation of a written instrument by parol evidence of a cotemporaneous or antecedent agreement.
There is a class of cases, in which parol proof is admissible, to show that there was a collateral agreement, co-temporaneous with the execution of anote, that the note might be discharged in a particular manner, provided the agreement has been executed. McNair and Wife v. Cooper, 4 Ala. 660; Murchie v. Cook & McNab, 1 Ala. 42; Honeycut v. Strother, 2 Ala. 135; Bradley v. Bentley, 8 Verm. 243; and Hagood v. Swords, 2 Bailey, 305, are all cases belonging to that class. They rest upon the idea, that when the parol agreement, as to the discharge of the note and its performance, has been proved, the note itself has not been varied, but the discharge of the note has merely been proved. The parol cotemporaneous agreement is admitted, not to vary the note, but to aid in the establishment of a subsequent satisfaction of it. This principle cannot apply here. To enable the administrator of Trawick to recover, it is necessary that he should not only show a discharge of the debt cieated by the advancement of money on the part of Jones, but that the bill of sale was subject to a parol condition, which, we have already decided, cannot be done in a court of law.
As this point is conclusive of the case, in a court of law, upon the facts before us, it is unnecessary to consider the other question argued at the bar.
The judgment of the court below is reversed, and the cause remanded.