Franz little knew that his words fell upon Beethoven like seed on eager soil.  From that time on he looked at Therese with different eyes.  His own love soon taught him to know that he was loved in return.  No pledge had yet passed between them when, in May, 1806, he went to Montonvasar on a visit; but one evening there, when Therese was standing at the piano listening to him play, he softly intoned Bach’s—­

  “Would you your true heart show me,
    Begin it secretly,
  For all the love you trow me,
    Let none the wiser be. 
  Our love, great beyond measure,
    To none must we impart;
  So, lock our rarest treasure
    Securely in your heart.”

Next morning they met in the park.  He told her that at last he had discovered in her the model for his Leonore, the heroine of his opera “Fidelio.”  “And so we found each other”—­these were the simple words with which, many years later, Therese concluded the narrative of her betrothal with Beethoven to Miriam Tenger.

The engagement had to be kept a secret.  Had it become known, it would have ended in his immediate dismissal by the Countess’ mother.  In only one person was confidence reposed, Franz, the devoted brother and treasured friend.  Therese’s income was small, and Franz, knowing the opposition with which the proposed match would meet, pointed out to Beethoven that it would be necessary for him to secure a settled position and income before the engagement could be published and the marriage take place.  The composer himself saw the justice of this, and assented.

[Illustration:  “Beethoven at Heiligenstadt.”  From the painting by Carl Schmidt.]

Early in July Beethoven left Montonvasar for Furen, a health resort on the Plattensee, which he reached after a hard trip.  Fatigued, grieving over the first parting from Therese, and downcast over his uncertain future, he there wrote the letter to his “Immortal Beloved,” which is now one of the treasures of the Berlin Library.  It is a long letter, much too long to be given here in full, written for the most part in ejaculatory phrases, and curiously alternating between love, despair, courage and hopefulness and commonplace, everyday affairs.  Nor will space permit me to tell how Alexander W. Thayer, an American, who spent a great part of his life and means in gathering detailed and authentic data for a Beethoven biography,—­which, however, he did not live to finish,—­worked out the year in which this letter was written (Beethoven gave only the day of the month); showed that it must be 1806; proved further that it could not have been intended for Giulietta Guicciardi, yet did not venture to state that Countess Therese Brunswick was the undoubted recipient.  Afterward, I believe, he heard of Miriam Tenger, entered into correspondence with her, and the letters doubtless will be found among his papers; but he did not live to make use of the information.