The Musical Offering: Bach’s Potsdam Encounter with Frederick the Great

On the evening of 7 May 1747, Frederick the Great was about to begin his usual private concert at Potsdam when he was handed the list of visitors to the town. According to the story told ever after, he put down his flute and told his musicians, “Gentlemen, old Bach has arrived.” What followed, an evening of improvisation on the king’s new keyboard instruments and a challenge set by the king himself, became one of the best-documented meetings in musical history. It gave the world the Musical Offering, a collection of fugues, puzzle canons and a trio sonata built on a single royal theme. Potsdam is a day trip early in our Bach: The Man, His Music small group tour, among the UNESCO-listed palaces and parks of Frederick the Great.

A son at a musical court

Bach had a family reason to be in Potsdam. His second son, Carl Philipp Emanuel, had served Frederick since around 1738, when Frederick was still crown prince, first as a harpsichordist in his household and from 1740, when Frederick became king, in the royal orchestra. He was promoted to chamber musician in 1746. Accompanying the king’s flute playing at the harpsichord was part of his daily work.

Frederick’s love of music had cost him dearly as a young man. His father, Frederick William I, regarded his interest in music, literature and French culture as effeminate and often beat and humiliated him for it. At his own small court at Rheinsberg before his accession, the crown prince gathered musicians and spent his evenings composing and playing, years he later remembered as among his happiest. As king he kept a distinguished musical establishment. The flautist and composer Johann Joachim Quantz, his flute teacher, joined the court in Berlin in December 1741 and stayed for the rest of his career. Our article on C. P. E. Bach in Hamburg follows Carl Philipp Emanuel after he left Frederick’s service in 1768.

The evening of 7 May 1747

Bach, now sixty-two, made the journey from Leipzig with his eldest son, Wilhelm Friedemann, according to the most familiar account. The newspapers of Berlin, Leipzig, Frankfurt, Hamburg and Magdeburg reported the visit within days, which shows how much attention it attracted. Frederick set aside his concert and had Bach brought straight to the palace. There he invited him to try his fortepianos, a new kind of keyboard instrument that could play loud and soft by touch. Frederick owned several, built by the Saxon maker Gottfried Silbermann, and Bach is said to have moved from room to room, improvising on each.

Then came the challenge. At Bach’s request, the king gave him a theme of his own, long and twisting with a chromatic descent, and Bach improvised a fugue in three voices on it on the spot. The king then asked for a fugue in six independent voices. Bach replied that not every theme suited such treatment and that he would need to work one out on paper, but he improvised a six-voice fugue on a theme of his own choosing instead, to the astonishment of those present. The next day he played the organs of Potsdam’s churches.

Improvisation as a court art

Improvising a fugue in front of a king was a particular kind of performance. A fugue takes a theme and passes it from voice to voice in strict counterpoint, so that each new entry has to fit everything already sounding. Doing that in three voices, in real time, on a theme you have just heard for the first time, demanded both technique and a mind that could plan several moves ahead. It was the musical equivalent of a chess master playing blindfold.

The theme itself, praised as “exceedingly beautiful” in accounts of the visit, was not an easy one. Its chromatic, falling line resists the neat combinations that make fugal writing work, which is part of why the six-voice version had to wait for the quiet of a study. For Bach, improvisation of this kind was not a party trick. It was how a German organist was judged, and the evening in Potsdam was in some ways the culmination of a career that had begun with organ trials in the churches of Thuringia.

From improvisation to print

Back in Leipzig, Bach kept his promise. He worked the king’s theme into a collection, finished it in July 1747 and had it engraved and printed. It went on sale at the Leipzig Michaelmas fair at the end of September, and on 30 September he advertised it in the Leipzig newspapers, listing two fugues, in three and six obligatory parts, a sonata for flute, violin and continuo, and various canons. The print was issued in three separate sections so that each could be used in practice.

The contents are a summary of what can be done with one theme. The two fugues are titled ricercar, an old-fashioned word for a learned contrapuntal piece. The three-part ricercar is generally taken to be a written version of what Bach improvised in Potsdam, and the six-part ricercar is the answer to the king’s challenge. Ten canons follow, some written in a riddling shorthand that leaves the performer to work out how the parts fit together. One is headed Quaerendo invenietis, “seek and you shall find”. Bach also printed a Latin inscription whose initial letters spell RICERCAR: Regis Iussu Cantio Et Reliqua Canonica Arte Resoluta, “the song commanded by the king, and the rest resolved by canonic art”.

Puzzles for a king

The canons are the most playful part of the collection. In a canon, one voice imitates another strictly, and Bach varies the rule each time. In the “crab” canon, one part plays the theme forwards while the other plays it backwards. In others the imitating voice turns the melody upside down, or plays it in longer note values. Several are printed as a single line with a clef or sign that hints at the solution, and players are left to work out where the second voice enters and how.

Bach added flattering Latin mottos to some of them. Beside the canon in augmentation, in which the notes grow longer, he wrote that the king’s fortune might grow with the notes. Beside the canon that rises a tone with each repetition, he wrote that the king’s glory might rise with the modulation. They are courtly compliments, but they are also jokes that only a reader who understands the musical device can share, which is exactly the kind of learned wit an Enlightenment court enjoyed.

A sonata for a royal flautist

The most direct compliment to the king is the trio sonata for flute, violin and continuo, in four movements, built on the royal theme. Frederick played the flute every evening with his musicians, and a sonata with a prominent flute part was music he could take into his own hands. It is the warmest and most approachable part of the collection, and it shows Bach writing in a style closer to the elegant taste of Frederick’s court than to the dense counterpoint of the canons.

The combination of learned puzzles and fashionable chamber music makes the Musical Offering a revealing portrait of Bach at sixty-two. He was writing for a younger, modern court whose taste had moved towards the lighter galant style that his son practised daily, and he answered with both: a sonata in the modern manner and a set of canons that showed the old learned art was still alive.

Bach and his royal patrons

The Musical Offering was not Bach’s first musical approach to a ruler. In 1721 he had sent six concertos to Christian Ludwig, Margrave of Brandenburg, a great-uncle of Frederick, the set we now call the Brandenburg Concertos and describe in our article on the Brandenburg Concertos and the Köthen court. In 1733 he presented a Kyrie and Gloria to the new elector of Saxony in Dresden, with a petition for a court title that he received in 1736, a story told in our article on Bach in Dresden.

Each gift used the same means: a beautifully prepared score, a respectful dedication and music chosen to show the full range of Bach’s art. The difference in 1747 was that the king had set the theme himself. The collection was both a gift and a public demonstration, advertised in the newspapers and sold at the fair, that Bach had met a royal challenge. Little is recorded of how Frederick received it.

Where did the meeting take place?

At the king’s residence in Potsdam, though contemporary reports do not name the room, and the next day Bach played the organs of the town’s churches. Potsdam was Frederick’s favourite place to live, and his summer palace of Sanssouci, above its terraced vineyards, was the residence where he spent much of his life and where he is buried. On the tour, the Potsdam day explores the UNESCO-listed palaces and parks of Frederick the Great, the setting of the court where Carl Philipp Emanuel worked for three decades.

How long is the Musical Offering, and how should you listen?

A complete performance usually takes around fifty minutes, though the order of the pieces is not fixed, since Bach printed them in separate sections. One modern edition suggests opening with the three-part ricercar, placing the trio sonata in the middle and ending with the six-part ricercar. A good way in is the trio sonata first, then the three-part ricercar, listening for the king’s theme in each, before tackling the canons, which reward repeated listening.

How demanding is the Potsdam day?

The Potsdam visit is a day trip from the group’s base in Berlin, with walking through the palace parks on gravel paths and some stairs and slopes, including terraces. The tour is rated Level 2 (Moderate): travellers should be able to manage stairs and take part in three to five hours of activity a day, the equivalent of walking up to eight kilometres on uneven ground.

The last journey

The visit to Potsdam was one of Bach’s last great public moments. Three years later, on 28 July 1750, he died in Leipzig after failed eye surgery, and his son Carl Philipp Emanuel stayed in Frederick’s service for nearly two more decades before moving to Hamburg. Our overview of Bach’s Germany shows how the tour begins with this late encounter in Potsdam and then travels back through his life.

Standing in Frederick’s palaces today, it is worth imagining the scene: an old cantor from Leipzig, as the story goes still in his travelling clothes, sitting down at an unfamiliar instrument while the king and his musicians gathered round, and turning a royal theme into a fugue as they listened. The Musical Offering is the written record of that evening, polished, extended and dedicated to the king who set the challenge.