In an action to foreclose a mortgage on real property, the appeal is from a judgment entered after trial before an Official Referee, dismissing the complaint. Judgment reversed on the law and the facts, without costs, and judgment of foreclosure and sale granted as demanded in the complaint. Findings of fact insofar as they may be inconsistent herewith are reversed and new findings are made as indicated herein. While the declarations of an alleged agent are not competent to prove the agency as against the alleged principal, the principal may prove the agency by the testimony of his agent. ( Steuerwald v. Jackson, 123 App. Div. 569. ) Although the testimony of the plaintiff's husband was erroneously excluded, the record establishes that there was an affirmative act, in exercise of the option to declare the principal mortgage indebtedness due, when plaintiff's attorney wrote a letter to that effect, notwithstanding that delivery of the letter was refused by the mortgagors. The option had been exercised prior to the time that the mortgagors offered to cure the default in payment of interest. (Cf. Albertina Realty Co. v. Rosbro Realty Corp., 258 N.Y. 472; Cresco Realty Co. v. Clark, 128 App. Div. 144.) No valid tender was made. (Civ. Prac. Act, § 174-a.) Nolan, P.J., Murphy, Ughetta, Hallinan and Kleinfeld, JJ., concur.