Bach Choir of Bethlehem

The Sanctus from The Mass in B Minor was the first movement Bach composed. Bach first wrote the Sanctus for a performance on Christmas Day, 1724.

The most noticeable characteristic of the Sanctus is Bach's use of combinations of three throughout this number. For example:

the text begins with 3 statements of the word "Sanctus" (holy). [Bach doesn't really have anything to do with that; that's how the text goes.]
Bach uses a six-part [that's 2 groups of 3] choir (2 sopranos, 2 altos, 1 tenor, and 1 bass part).
He also uses 3 trumpets, and 3 oboes.
In the music, Bach uses a lot of triplets (dividing
the beat into 3 equal parts).
When the text changes to "pleni sunt coeli et terra gloria ejus" ("heaven and earth are full of your glory"), Bach changes the meter to 3/8, where each measure contains 3 eighth notes.
The Mass in B Minor begins in B minor, but the Sanctus begins in D major - 3 letters away, if you begin counting on B.
Bach also specified that each of the choirs of musicians must have "at least 3 sopranos, 3 contraltos, 3 tenor, and the same number of basses (3)."

So what, you might ask? Well, Bach often used 3s in his music, because to him, 3 was a direct reference to God, who to many Christians, is a triune God. That means, three persons - God the Father, God the Son, and God the Holy Spirit - in one God.

We've already talked a little about the text, but here it is in its entirety:

Sanctus, sanctus, sanctus
Dominus Deus Sabaoth,
Pleni sunt coeli et terra
Gloria ejus.

Holy, holy, holy
Lord God of power and might
Heaven and earth are full
Of your glory.

You might notice that this is a relatively short text. Because of this, Bach is able to use a great deal of text repetition, something composers generally don't do with long texts. (The Credo, for example, has about 40 lines of text.) The repetitions help to emphasize specific words in the text as well as create an overall mood of joy and fullness-as in "heaven and earth are full of your glory."

Bach's musical setting is also bright and joyful. He uses three trumpets to give the music brilliance. The six-part choir allows for varieties of texture, especially with lot of passages of imitation that reflect the many different people on earth.

Perhaps even more breathtaking is the second half of the Sanctus, the part beginning with the text "Pleni sunt coeli et terra." After the luxurious, extended repetitions of the first part of the text ("Sanctus, sanctus, sanctus, Dominus Deus Sabaoth"), the next section begins with a change of tempo, meter, and texture. Also, Bach uses a particular form here known as a fugue. In a fugue, a theme (called the "subject") is introduced by one part (here, the tenors) without accompaniment. When the tenors finish, then another part (here, alto 2) begins the subject, while the tenor continues singing other material. This continues as the soprano 1, soprano 2 & alto 1 together, and finally the basses enter singing the subject. As the texture fills, you really get the sense that heaven and earth are filled with God's glory, just as the words tell us. The subject, as the tenors sing it, is pictured below:

You might also notice that Bach writes a melisma on each statement of the word "gloria." A melisma occurs when a composer writes more than one note on a single syllable, as Bach does here: By doing this, Bach puts extra emphasis on the word "gloria," in a sense, giving it glory, just as heaven and earth give glory to God. This is an example of "word painting"-when the composer writes music that demonstrates what the words tell us.