Hedwig Fassbender
... that mezzo-soprano Hedwig Fassbender, who also appeared in soprano roles such as Wagner's Isolde, has been an influential voice teacher in Frankfurt?
... that mezzo-soprano <b id="mwAuo"><a href="./Hedwig_Fassbender" id="mwAus" rel="mw:WikiLink" title="Hedwig Fassbender">Hedwig Fassbender</a></b>, who also appeared in soprano roles such as Wagner's <a href="./Tristan_und_Isolde" id="mwAuw" rel="mw:WikiLink" title="Tristan und Isolde">Isolde</a>, has been an influential voice teacher in <a href="./Frankfurt_University_of_Music_and_Performing_Arts" id="mwAu0" rel="mw:WikiLink" title="Frankfurt University of Music and Performing Arts">Frankfurt</a>?