Bach - Agnus Dei

Context within work, genre

• From the Last section of the B minor mass.
• Solo aria, followed by a chorus
• Alto solo, violin ritornello with a low tessitura - low lying violin melody
• Obbligato aria - have to have instrumental line interlinking with solo voice line - Violin line esential
• This music is from one of his earlier works
• Old style of composition - elaborate
• Prima prattica - old style - first style, some harmonic features more elaborate

Text and text setting

• "Lamb of God, who takes away the sins of world, have mercy on us".
• Minor tonality - starts in G, opening 8 bars set the tone for these words.
• Opening ritornello has lots of features which give it a lamenting feel
• Poignant intervals, eg: diminished 5th :F# to C ( bar 2) and uses diminished 7th in violin ritornellos, chromatic shapes who add to this feel.
• Pairs of slurred quavers also, sometimes we get an appogiatura.
• Most syllabic setting apart from the word " Misere" - means mercy - always melismatic
• Opening vocal melody descends, which gives a depressing feel.

Melody and Rhythm

• Ritornello melody uses some particular motifs
• 1st melody has an arpeggiated shaped - disjunct and angular.
• Uses of diminished 5ths and 7ths throughout. Bach often used angular shapes and pattern refers to under scale of work
• Second idea (bar 3), uses slurred quavers, some of them being appogiaturas
• The rests in the continuo creates a sigh- like feel
• Vocal line: Descends, long phrases especially in bar 17 - "misere" - goes on.
• Irregular phrase lenths, unsettling
• In places, vocal line quite linear, beginning tune "agnus dei"
• In other places, not so linear and has lots of chromatisism for example when the melody is in D minor (bar 27)
• 1st melody is sequential
• Lots repeated

Tonality and Harmony

• Starts in G minor (The tonic)
• Bar 27: D minor (the dominant)
• Bar 31: Returns to G minor ( The tonic) with some examples of dissonance (bar 1) also a chromatically altered chord (beat of bar 1) - Not what you'd expect
• A dissonance between C in violins and G in basso in bar 1.
• Use of Neopolitan 6th, bar 2 - Ab chord in 1st inversion- goes through Dminor in bar 4.
• Moves to C minor in second half of bar 5
• Uses diminshed triads in harmony
• Diminshed 7th full in bar 7
• False relations in bar 9, F followed by F# in bar 14, Ab moves to A natural in bar 18.
• Generally, very chromatic harmony.

Texture

• Instrumental: 2 part texture, when the voice comes in; its a three part texture
• Its broadly a contrapuntel texture. Bar 13, 14, immitation between voice and violin.
• The violin obbligato, immitates the voice.
• A canon when the voice first comes in between the voice and violin obbligato - cannon at the 5th.
• Bar 17, violins play ritornello from the opening melody against the melody in the voice
• Bar 31 - repeats canon at the 5th

Structure

• Ritornello form. Bars 1-8 opening ritornello.
• Bar 9 - Vocal melody comes in A section.
• Bar 13 - ritornello in violin part
• Bar 17 - move to D minor and ritornello material in violins
• Not as sectional as laudamus te, less ritronellos but in bar 23 there is 4 bars of ritornello, intergrated with voice, with the ritornello against it. Bar 27, back to beginning melody but chnages direction. Bar 31 mmoves back to Gminor.
• Short ritornello in D minor in middle of aria, opening melody in bar 9 is reprised in bar 31.
• The structure has similiarities with Laudmaus te but not such clear divisions between sections.