While Bonn was politically and culturally affiliated to Vienna,[2] it was geographically even more remote than Salzburg, lying around 900 km distant on the opposite side of German-speaking Europe.[8] Beethoven's return to Bonn was prompted at least in part by his mother's medical condition (she died of tuberculosis in July of that year[9]).Beethoven was not intimidated, and worked out the subject, the secret intention of which he immediately perceived, at great length and with such remarkable originality and power that Mozart's attention was riveted, and his wonder so excited that he stepped softly into the adjoining room where some friends were assembled, and whispered to them with sparkling eyes: "Don't lose sight of this young man, he will one day tell you some things that will surprise you!In the absence of documents, much remains uncertain about the precise aims of the journey and the extent to which they were realized; but there seems little doubt that he met Mozart and perhaps had a few lessons from him.[14]Solomon goes on to enumerate other matters that kept Mozart preoccupied at the time: his father's declining health, a visit to Prague, the beginnings of work on Don Giovanni, and the writing of "a vast amount of other music".The Grove Dictionary notes that his "first surviving letter, to a member of a family in Augsburg that had befriended him on his way [to Vienna], describes the melancholy events of that summer and hints at ... ill-health [and] depression.Like Mozart, Beethoven early established a strong reputation as a keyboard performer, was mentored by Joseph Haydn, and was given patronage by Countess Maria Wilhelmine Thun.On the Prague phase of his journey, Beethoven composed an extended concert aria for the noted soprano Josepha Duschek, as Mozart had done on his visit in 1789.