Bach: Musikalisches Opfer, BWV 1079

Introduction

The Musical Offering (German title: Musikalisches Opfer or Das Musikalische Opfer), BWV 1079, is a collection of keyboard canons and fugues and other pieces of music by Johann Sebastian Bach, all based on a single musical theme given to him by Frederick the Great (Frederick II of Prussia), to whom they are dedicated. The Ricercar a 6, a six-voice fugue which is regarded as the highpoint of the entire work, was put forward by the musicologist Charles Rosen as the most significant piano composition in history (partly because it is one of the first). This ricercar is also occasionally called the Prussian Fugue, a name used by Bach himself. The composition features in the opening section of Douglas Hofstadter's Pulitzer Prize winning book Gödel, Escher, Bach (1979).

History

The collection has its roots in a meeting between Bach and Frederick II on May 7, 1747. The meeting, taking place at the King's residence in Potsdam, came about because Bach's son Carl Philipp Emanuel was employed there as court musician. Frederick wanted to show the elder Bach a novelty, the fortepiano, which had been invented some years earlier. The King owned several of the experimental instruments being developed by Gottfried Silbermann. During his anticipated visit to Frederick's palace in Potsdam, Bach, who was well known for his skill at improvising, received from Frederick a long and complex musical theme on which to improvise a three-voice fugue. He did so, but Frederick then challenged him to improvise a six-voice fugue on the same theme. Bach answered that he would need to work the score and send it to the King afterwards. He then returned to Leipzig to write out the Thema Regium ("theme of the king"):

Two months after the meeting, Bach published a set of pieces based on this theme which we now know as The Musical Offering. Bach inscribed the piece "Regis Iussu Cantio Et Reliqua Canonica Arte Resoluta" (the theme given by the king, with additions, resolved in the canonic style), the first letters of which spell out the word ricercar, a well-known genre of the time.

The "thema regium" appears as the theme for the first and last movements of Sonata No. 7 in D minor by Friedrich Wilhelm Rust, written in about 1788, and also as the theme for elaborate variations by Giovanni Paisiello in his "Les Adieux de la Grande Duchesse de Russies," written in about 1784, upon his departure from the court of Catherine the Great.

Possible origin of the King's Theme

Humphrey F. Sassoon has compared the theme issued by Frederick II to the theme of an A minor fugue (HWV 609) by George Frideric Handel, published in Six fugues or voluntarys for organ or harpsichord. Sassoon notes that "Handel's theme is much shorter than the King's, but its musical 'architecture' is uncannily similar: jumps followed by a descending chromatic scale." He also elaborates on their additional similarities, which led Sassoon to suggest that Bach used Handel's A minor fugue as a structural model or guide for the Musical Offering's Ricercar a 6, and that its musical concepts may also have influenced Bach's development of the Ricercar a 3. Nevertheless, the Ricercar a 6 is longer and incomparably more complex than Handel's fugue.

Structure and instrumentation

In its finished form, The Musical Offering comprises:

• Two Ricercars, written down on as many staves as there are voices:
  • a Ricercar a 3 (a three-voice fugue)
  • a Ricercar a 6 (a six-voice fugue)
• Ten Canons:
  • Canones diversi super Thema Regium:
    • 2 Canons a 2 (the first representing a notable example of a crab canon or canon cancrizans)
    • Canon a 2, per motum contrarium
    • Canon a 2, per augmentationem, contrario motu
    • Canon a 2, per tonos
  • Canon perpetuus
  • Fuga canonica in Epidiapente
  • Canon a 2 "Quaerendo invenietis"
  • Canon a 4
  • Canon perpetuus, contrario motu

• A Sonata sopr'il Soggetto Reale – a trio sonata featuring the flute, an instrument which Frederick played, consisting of four movements:
  • Largo
  • Allegro
  • Andante
  • Allegro

Apart from the trio sonata, which is written for flute, violin and basso continuo, the pieces have few indications of which instruments are meant to play them, although there is now significant support for the idea that they are for solo keyboard, like most of Bach's other published works.

The ricercars and canons have been realised in various ways. The ricercars are more frequently performed on keyboard than the canons, which are often played by an ensemble of chamber musicians, with instrumentation comparable to that of the trio sonata.

As the printed version gives the impression of being organised for convenient page turning when sight-playing the score, the order of the pieces intended by Bach (if there was an intended order) remains uncertain, although it is customary to open the collection with the Ricercar a 3, and play the trio sonata toward the end. The Canones super Thema Regium are also usually played together.

Musical riddles

Some of the canons of The Musical Offering are represented in the original score by no more than a short monodic melody of a few measures, with a more or less enigmatic inscription in Latin above the melody. These compositions are called the riddle fugues (or sometimes, more appropriately, the riddle canons). The performer(s) is/are supposed to interpret the music as a multi-part piece (a piece with several intertwining melodies), while solving the "riddle". Some of these riddles have been explained to have more than one possible "solution", although nowadays most printed editions of the score give a single, more or less "standard" solution of the riddle, so that interpreters can just play, without having to worry about the Latin, or the riddle.

One of these riddle canons, "in augmentationem" (i.e. augmentation, the length of the notes gets longer), is inscribed "Notulis crescentibus crescat Fortuna Regis" (may the fortunes of the king increase like the length of the notes), while a modulating canon which ends a tone higher than it starts is inscribed "Ascendenteque Modulatione ascendat Gloria Regis" (as the modulation rises, so may the King's glory).

Canon per tonos (endlessly rising canon)

The canon per tonos (endlessly rising canon) pits a variant of the king’s theme against a two-voice canon at the fifth. However, it modulates and finishes one whole tone higher than it started out at. It thus has no final cadence.