Gertrude Förstel
... that Gertrude Förstel was Sophie when Der Rosenkavalier was first performed in Vienna, and sang in the premieres of Tiefland and Mahler's Eighth Symphony?
... that <b id="mwIg"><a href="./Gertrude_Förstel" id="mwIw" rel="mw:WikiLink" title="Gertrude Förstel">Gertrude Förstel</a></b> was Sophie when <i id="mwJA"><a href="./Der_Rosenkavalier" id="mwJQ" rel="mw:WikiLink" title="Der Rosenkavalier">Der Rosenkavalier</a></i> was first performed in Vienna, and sang in the premieres of <i id="mwJg"><a href="./Tiefland_(opera)" id="mwJw" rel="mw:WikiLink" title="Tiefland (opera)">Tiefland</a></i> and Mahler's <a href="./Symphony_No._8_(Mahler)" id="mwKA" rel="mw:WikiLink" title="Symphony No. 8 (Mahler)">Eighth Symphony</a>?