HANEY, J.
This is an action to enforce the specific .performance of two contracts in writing relating to real property. The appeal is by the plaintiff from a judgment in favor of the defendant and from an order denying plaintiff's application for a new trial.
*436On March 30, 1908, the defendant and one W. H. Fuller executed two contracts, in each of which the defendant agreed to convey to the latter, by warranty deed, a fee-simple title to a quarter section of land in Sully county, subject to a mortgage thereon, upon payment of certain specified sums on or before certain specified dates, with interest at the rate of 8 per cent, per annum; and in each of which Fuller agreed to make the specified payments, to assume the mortgage, to pay tax.es, and to break 25 or more acres of the quarter before June 1, 1908. Fuller made the payment required by each contract when it was executed, paid taxes for one year,- broke more than 25 acres of each quarter before June 1, 1908, and placed valuable improvements on the land, but failed to make payments required by each contract November 1, 1908, and November r, igog. On April 19, 1909, Fuller executed, acknowledged, and delivered to the plaintiff the following instrument, which was recorded April 24, 1909: “Know all men by these presents, that I, W. H. Fuller, for and in consideration of the sum of one dollar to me in hand paid by J. T. Case Threshing Machine Company (Incorporated), hereby sell, assign, and set over to the said J. I. Case Threshing Machine Company (Incorporated) all my right, title, and interest in and to that certain land contract bearing date of the 30th day of March, 1908, and described as follows, viz.: * * * And I hereby represent that there is now remaining unpaid on said contract the sum of $t,200.00 and that there are no unpaid sums past due either of interest or principal. The object of this assignment is to secure to the J. I. Case Threshing Machine Company (Incorporated) the payment to it of the sum of $3,200.00, according to the terms of seven certain promissory notes as follows: * * * I further agree that if the said J. 1. Case Threshing Machine Company (Incorporated) shall make payments on said contract, either of principal, interest, or taxes, this assignment shall operate as security for the repayment to it of all sums so paid with interest from date of payment at the rate of ten per cent, per annum. I hereby authorize the owner of said land to deed the same to the J. I. Case Threshing- Machine Company (Incorporated) when the terms of said contract have been fully complied with. It is further mu*437tually agreed that when all sums secured by this assignment shall have been paid in full to the J. I. Case Threshing Machine Company (Incorporated), with interest, then and in that event the said company will reassign said contract to the said W. H. Fuller, and if said lands shall have been deeded to said company then said company will reconvey them by a sufficient deed covenanting only against its own acts and subject to all unpaid taxes and incumbrances to the said W. H. Fuller upon the completion of said payments, but nothing herein contained shall be construed as a covenant or agreement on the part of said company to assume or pay any part of the purchase price of said lands or any taxes or incumbrances thereon. I, the said W. H. Fuller, hereby agree that I will make all payments to be made according to the terms of said contract and will make same when they become due according to the terms of said contract.” On January io, 1910, the plaintiff notified the defendant in writing that it was the owner by assignment of all the vendee’s right, title, and interest in and to both contracts; that it elected to pay all that remained unpaid, with interest, according to the terms of the contracts (payments before maturity at option of vendee being permitted by both) ; that it would assume payment of the mortgages; and demanded the transfer of a merchantable title by warranty deed subject to the mortgages. On the same day the plaintiff tendered to the defendant $3,626.12, again demanding performance by the defendant, deposited the sum so tendered, and notified the defendant of the deposit.
[1] The contracts sought to be enforced are not the same in form or substance. One expressly declares that time shall be of the essence of the obligation, while the other does not. One provides for the filing of a declaration of forfeiture by the vendor with the register of deeds in case the contract shall have been recorded, while the other has no such provision. Notwithstanding the substantial difference between the contracts in these and other respects, the action appears to have been tried as though it involved only one contract — only one cause of action — the defendant having been allowed to introduce two declarations of forfeiture *438filed November 30, 1909. Manifestly the declaration relating to the contract which contained no reference to such an instrument was immaterial and should have been excluded. Nor should the other have been received in absence of evidence that the contract' to which it related had been recorded. Moreover, assuming both contracts authorized the filing of these declarations, the fact that they were filed was immaterial because the defendant was not in position to declare a forfeiture.
[2] As to the contract wherein time was not expressly declared to be of the essence of the obligation, the delay being capable of exact and entire compensation by the payment of interest, the vendee’s failure to make payments when due did not justify refusal to accept payment when offered by the plaintiff. Rev. Civ. Code, § 1158.
[3] If time had been expressly declared to be of the essence of the obligation in both contracts, the defendant was not in position to insist upon a forfeiture. She had not only neglected to promptly assert her rights, but had, as appears from uncontradicted evidence, on December 1, 1908, after the vendee was in default, accepted a payment of interest, stating, “There, that settles that for one year.” It may be that the receipts for this interest did not show an agreement to extend any payment, and that the payment of accrued interest was not sufficient consideration to support an oral extension; nevertheless, the defendant’s conduct operated as a waiver of her right to insist upon a strict compliance with the terms of either contract as to the time of payment. Pier v. Lee, 14 S. D. 600, 86 N. W. 642; Keator v. Ferguson, 20 S. D. 473, 107 N. W. 678, 129 Am. St. Rep. 947.
[4] The trial court found that on or about November 15, 1909, the defendant demanded of the vendee payment in full for all of the lands in accordance with the terms of the contracts. If this means that immediate payment was demanded, it constituted no defense as the vendee was entitled to a reasonable time in which to perform; strict compliance with the terms of the contract, as to the time of payment, -having been previously waived by the vendor.
*439[5] But no demand was alleged; none was proved. The only testimony on the subject is that of the vendee. It is as follows: “I went to see her at Doland the 2d of November, 1909, about the payment of the balance of her -money. I stated to her that I wanted to sell the place. I was thinking then of selling only one quarter. Q. What did you say about wanting a deed? A. She said she was willing to take her money and give a deed, but she wanted all her money. I told her the money was ready for one quarter, that I would have to see about the money for the other quarter. I afterwards wrote her and she came over. That was along about the 15th of last November. Q. What did you say to her at that time about paying her all of her money and taking deeds for both quarters of land? A. She said she was ready to take it, but she said the' Case people having this assignment — as quick as we could get that straightened she wpuld give a deed.” This testimony discloses nothing more than an unjustifiable refusal to deed one quarter without receiving all that was due on both contracts. It conclusively establishes the fact that the defendant was not then intending to declare a forfeiture'as to either. Actual notice of the filing of the declarations was not given to the vendee or to his assignee, nor was actual notice of the defendant’s intention to declare a forfeiture given to any one, so far as the record on this appeal discloses, before this action was commenced. Therefore, if the vendee were plaintiff, the defendant could not successfully resist specific performance on the ground of the former’s failure to make payments when due by the terms of the contracts.
[6] There was nothing in the nature or terms of either contract which precluded its assignment. There was no uncertainty as to validity or terms. The vendor’s' obligation was to convey a merchantable title, subject to the mortgages, upon certain definite, specified conditions. It was wholly immaterial in whom such title should vest, provided such conditions were complied with. The recorded assignment, expressly authorizing the defendant to convey 'to the plaintiff, protected her against any demands of the vendee. Ross v. Page, 11 N. D. 458, 92 N. W. 822.
*440[7] Why then should she not have been compelled to convey upon the specified conditions? The record discloses no evidence as to the value of the property at any time; no suggestion of fraud, mistake, duress, or undue influence; no fact which rendered specific performance upon the specified conditions unjust or unreasonable. The vendee having partially performed, and the failure to promptly pay the 'sums required by the contracts, including the mortgages mentioned therein, when they became due, being capable of exact and entire compensation by payment of interest and repayment of whatever sums were paid on the mortgages by the defendant, with interest, the case was one in which specific performance is expressly authorized by the statute. Rev. Civ. Code, § 2346.
[8] The contention that the plaintiff was not entitled to specific performance because the assignment provided that “nothing herein contained shall be construed as a covenant or agreement on the part of said company to assume or pay any part of the purchase price of said lands or any taxes or incumbrances thereon” is not tenable. It rests on these statutory provisions: “Neither party to an obligation can be compelled specifically to perform it, unless the other party thereto has performed, or is compellable specifically to perform, everything to which, the former is entitled under the same obligation, either completely or nearly so, together with full compensation for any want of entire performance.” Rev. Civ. Code, § 2340. This statute is merely declaratory of the well-recognized rule that in this class of cases there must be mutuality of remedy when the decree is rendered. It does not require mutuality of remedy ab initio. If, when the decree is rendered, the party seeking specific performance .has fully performed, or may be compelled to fully perform, the rule and the reason of the rule are satisfied. It simply requires that the court, by its decree, shall enforce all the unperformed provisions of the contract in prasenti. Brown v. Munger, 42 Minn. 482, 44 N. W. 519. When the decree in this case was rendered, both mortgages on the land had been .paid.by the defendant, the provisions relating to breaking had been performed, and the plaintiff was in court insisting upon the right *441to repay whatever sums had been paid by the defendant on taxes and the mortgages, with interest, and to pay whatever sums were due the defendant by the terms of the contract, with interest. A decree compelling the defendant to convey upon receiving all she would have received for her land had the contracts been performed according to their terms, with interest as compensation for the delay, would have enforced all unperformed conditions of both contracts; would have given the defendant what she agreed to accept for her land; and would have been entirely just and equitable. There can be no doubt of the court’s power to have rendered such a decree. Therefore there was mutuality of remedy within the meaning of the statute.
[9] The notice of deposit required defendant to furnish abstracts of title, a condition not justified by either contract. The evidence discloses that the defendant had paid certain taxes and certain sums as interest on the mortgages, which, as we understand the record, were not included in the plaintiff’s tender, presumably because the fact of such payments by the defendant was unknown to the plaintiff when its tender was made. The evidence also discloses that, after plaintiff’s tender and before the trial, the defendant paid both mortgages. On the trial, the plaintiff offered to repay all sums paid by the defendant, with interest. This offer, in connection with the tender, in absence of any objections to the tender, clearly entitled the latter to be heard on the merits of its cause of action. Rev. Civ. Code, § 1167. Montgomery v. De Picot, 153 Cal. 509, 96 Pac. 305, 126 Am. St. Rep. 84. The fundamental principle governing this phase of the case is the maxim that “He who seeks equity must do equity.” It conclusively appears that the plaintiff was ready, able, and willing to perform all the unperformed conditions of both contracts; to compensate the plaintiff by repayment, with interest, for all payments made by her; and that it would have done so if permitted by the defendant or required by the trial court.
[10] The expressions frequently found in the books regarding the discretionary powers of courts of equity, in actions to compel the specific performance of contracts, unless taken with certain *442limitations, are misleading. They do not mean that judgments in such actions may not be reviewed and reversed if found erroneous. When, as in this case, the material facts are established by undisputed evidence, “the principles of equity come into operation and pronounce with certainty and absoluteness whether the remedy shall be granted or withheld.” Pomeroy on Contracts, § 46. Upon the undisputed facts disclosed by the record on this appeal, we think the remedy should not have been withheld. The judgment and order appealed from are reversed.