The tragic prelude to Act III instantly plunges us into the dark realm towards obvlivion. The Tristan Progression is now funereal, an F minor plagal progression sounding impossibly deep in the strings. T This is what Richard Strauss imitated in Death and Transfiguration. This opening of deep gloom is the place Tchaikovsky went to for his Symphony Pathetique. Mahler as well hearkened to this Act III Tristan opening in his own sublime masterpiece, The Farewell, from Das Lied von der Erde. It is also music Wagner himself composed earlier in his song Im Treibhaus (In the Greenhouse) from his Wesendock Lieder, a song that imagines the drooping tall plants in sorrow of mortality.