Tristan as the heroic slayer of Isolda’s betrothed, Morold.  Brangaena precipitately retreats and closes the curtains; Isolda and she face one another in the tent, the second nearly prostrate with dismay, the first boiling with wrath and shame at the insult hurled at her.  She now tells Brangaena the whole of the preceding history—­her nursing of Tristan and his monstrous treatment of her—­and finishes with another curse.  Brangaena tries to soothe her; Isolda, outwardly quietened, inwardly is planning how to carry out her purpose; Brangaena unknowingly suggests the means.  “In that casket is a love potion:  drink that, you will love your aged bridegroom and be happy once again.”  She opens the casket; “not that phial,” says Isolda, “the other.”  The poison motive (c) sounds under the agitated upper strings:  “the deadly draught,” Brangaena shrieks:  at this point the shouting of the sailors is heard as they begin to shorten sail; Kurvenal enters brusquely and bellows at Isolda the order to prepare to land.  She refuses to move until Tristan has come in to ask her pardon “for trespass black and base.”  Here she begins to speak in terrible double-meanings:  it is not Tristan’s discourtesy on the voyage he must apologise for, but the more tragic occurrences leading up to his bearing her away to Cornwall.  She orders Brangaena to prepare the draught, and awaits her victim.

She stands there outwardly composed while one of the finest passages in the whole of the world’s music betrays her inward anxiety and suspense (i).  It is useless to describe the scene in any detail:  the words are simple and seemingly direct; the marvellous music alone reveals their fateful, fearful significance.  Isolda asks Tristan to sink the ancient quarrel between them—­caused by the slaying of Morold—­and drink a cup together; he knows perfectly well a large part of her meaning—­that she means to poison him.  Whether she herself intends what presently occurs no one can tell:  I doubt whether Wagner knew much or cared at all.  Tristan knows how great is the crime he must make amends for:  not merely Morold’s death, but the winning of Isolda’s heart, the desertion, the cruel coming to claim her as his uncle’s bride; he says he will drink—­only in oblivion can he find refuge from the toils in which he has involved himself; he lifts the cup to his lips, drinks, and as he drinks Isolda, crying “Betrayed, even here,” snatches the cup from him and drains it.

Brangaena has betrayed her:  the cup contains not the poison but the love-potion.  In this stroke there is no fairy-tale or pantomime foolery.  The course the drama now pursues is determined not by a magic draught, a harmless infusion of herbs, but by the belief of the lovers that they have taken poison and are both doomed.  Whether Tristan had previously known Isolda to love him does not matter:  he knows it now.  It has been remarked that the language is ambiguous:  or rather, Isolda in her