"" (K. 316/300b) is a recitative and aria for soprano and orchestra that Wolfgang Amadeus Mozart wrote for Aloysia Weber. It is famous for including two occurrences of a G6, i.e. the G above high C, or 1568 Hz by modern concert pitch – according to the Guinness Book of Records, the highest musical note ever scored for the human voice. (However, an A6 is scored in Ignaz Umlauf's Das Irrlicht, also sung by Aloysia Weber.) History Mozart completed this recitative and aria in Munich on 8 January 1779, as an insertion aria for the opera Alceste by Christoph Willibald Gluck. It was written specifically to showcase the superlative vocal skills of Mozart's future sister-in-law, Aloysia Weber, who was only 18 at the time. However, sopranos who are able to cope with the aria's demands have been few and far between, and hence the aria is usually omitted from performances of Alceste. It has been therefore redesignated a concert aria, to be presented in concerts by such rare singers as are able to deliver its fiendishly difficult coloratura. Music The aria is scored for solo oboe, solo bassoon, 2 horns in C, and strings. The opening recitative is 47 bars long and is in C minor with a time signature of , with the detailed tempo direction Andantino sostenuto e languido. The following aria is 192 bars long and in C major. The aria is divided into two parts: the first part with a time signature of and tempo Andantino sostenuto e cantabile, ends in bar 85; the second part then begins, and the tempo then accelerates to Allegro assai to the words of the final four lines. The aria has a vocal range of two octaves and a major second (or 2500 cents), from F4 to G6; the latter note occurs only twice (in bars 165 and 172 of the aria): Libretto The text of the aria is from the opera Alceste, and was written by Ranieri de' Calzabigi. It is inserted at act 1, scene 2. Popoli di Tessaglia, ah mai più giusto fu il vostro pianto; a voi non men che a questi innocenti fanciulli Admeto è padre. Io perdo il caro sposo, e voi l'amato re. La nostra sola speranza, il nostro amor c'invola questo fato crudel, né so chi prima in sì grave sciagura a compianger m'appigli del regno, di me stessa, o de' miei