• Composer, Organist and Violinist Johann Sebastian Bach, 1685

   

Bach was born in Eisenach, Saxe - Eisenach, into a very musical family; his father, Johann Ambrosius Bach was the director of the town musicians, and all of his uncles were professional musicians. His father taught him to play violin and harpsichord, and his brother, Johann Christoph Bach, taught him the clavichord and exposed him to much contemporary music. Bach also went to St Michael's School in Lüneburg because of his singing skills. After graduating, he held several musical posts across Germany: he served as Kapellmeister (director of music) to Leopold, Prince of Anhalt - Köthen, Cantor of Thomasschule in Leipzig and Royal Court Composer to August III. Bach's health and vision declined in 1749, and he died on 28 July 1750. Modern historians believe that his death was caused by a combination of stroke and pneumonia.

Bach's abilities as an organist were highly respected throughout Europe during his lifetime, although he was not widely recognized as a great composer until a revival of interest and performances of his music in the first half of the 19th century. He is now generally regarded as one of the main composers of the Baroque period, and as one of the greatest composers of all time.

Johann Sebastian Bach was born in Eisenach, Saxe - Eisenach, on 21 March 1685 O.S. (31 March 1685 N.S.). He was the son of Johann Ambrosius Bach, the director of the town musicians, and Maria Elisabeth Lämmerhirt. He was the eighth child of Johann Ambrosius, (the eldest son in the family was 14 at the time of Bach’s birth) who was likely to have taught him violin and the basics of music theory. His uncles were all professional musicians, whose posts included church organists, court chamber musicians and composers. One uncle, Johann Christoph Bach (1645 - 93), introduced him to the organ, and an older second cousin, Johann Ludwig Bach (1677 - 1731), was a well known composer and violinist. Bach drafted a genealogy around 1735, titled "Origin of the musical Bach family".

Bach's mother died in 1694, and his father died eight months later. Bach, 10, moved in with his oldest brother, Johann Christoph Bach (1671 - 1721), the organist at the Michaeliskirche in Ohrdruf, Saxe - Gotha - Altenburg. There he studied, performed and copied music, including his own brother's, despite being forbidden to do so because scores were so valuable and private and blank ledger paper of that type was costly. He received valuable teaching from his brother, who instructed him on the clavichord. J.C. Bach exposed him to the works of great composers of the day, including South German composers such as Johann Pachelbel (under whom Johann Christoph had studied) and Johann Jakob Froberger; North German composers; Frenchmen, such as Jean - Baptiste Lully, Louis Marchand, Marin Marais; and the Italian clavierist Girolamo Frescobaldi. Also during this time, he was taught theology, Latin, Greek, French and Italian at the local gymnasium.

At the age of 14, Bach, along with his older school friend George Erdmann, was awarded a choral scholarship to study at the prestigious St. Michael's School in Lüneburg in the Principality of Lüneburg. Although it is not known for certain, the trip was likely taken mostly on foot. His two years there were critical in exposing him to a wider facet of European culture. In addition to singing in the choir he played the School's three - manual organ and harpsichords. He came into contact with sons of noblemen from northern Germany sent to the highly selective school to prepare for careers in other disciplines.

Although little supporting historical evidence exists at this time, it is almost certain that while in Lüneburg, Bach visited the Johanniskirche (Church of St. John) and heard (and possibly played) the church's famous organ (built in 1549 by Jasper Johannsen, and played by Georg Böhm). Given his musical talent, Bach had significant contact with prominent organists of the day in Lüneburg, most notably Böhm, but also including organists in nearby Hamburg, such as Johann Adam Reincken.

In January 1703, shortly after graduating from St. Michael's and being turned down for the post of organist at Sangerhausen, Bach was appointed court musician in the chapel of Duke Johann Ernst in Weimar. His role there is unclear, but likely included menial, non-musical duties. During his seven month tenure at Weimar, his reputation as a keyboardist spread so much that he was invited to inspect the new organ, and give the inaugural recital, at St. Boniface's Church in Arnstadt, located about 40 km southwest of Weimar. In August 1703, he became the organist at St Boniface's, with light duties, a relatively generous salary, and a fine new organ tuned in the modern tempered system that allowed a wide range of keys to be used.

Despite strong family connections and a musically enthusiastic employer, tension built up between Bach and the authorities after several years in the post. Bach was dissatisfied with the standard of singers in the choir, while his employer was upset by his unauthorized absence from Arnstadt; Bach was gone for several months in 1705-06, to visit the great organist and composer Dieterich Buxtehude and his Abendmusiken at the Marienkirche in the northern city of Lübeck. The visit to Buxtehude involved a 400 kilometer (250 mi) journey on foot each way. The trip reinforced Buxtehude's style as a foundation for Bach's earlier works. Bach wanted to become amanuensis (assistant and successor) to Buxtehude, but did not want to marry his daughter, which was a condition for his appointment.

In 1706, Bach was offered a post as organist at St. Blasius's in Mühlhausen, which he took up the following year. It included significantly higher remuneration, improved conditions, and a better choir. Four months after arriving at Mühlhausen, Bach married Maria Barbara Bach, his second cousin. They had seven children, four of whom survived to adulthood, including Wilhelm Friedemann Bach and Carl Philipp Emanuel Bach who both became important composers as well. Bach was able to convince the church and city government at Mühlhausen to fund an expensive renovation of the organ at St. Blasius's. Bach, in turn, wrote an elaborate, festive cantata — Gott ist mein König, BWV 71 — for the inauguration of the new council in 1708. The council paid handsomely for its publication, and it was a major success.

In 1708, Bach left Mühlhausen, returning to Weimar this time as organist and from 1714 "Konzertmeister", director of music, at the ducal court, where he had an opportunity to work with a large, well funded contingent of professional musicians. Bach moved with his family into an apartment very close to the ducal palace. In the following year, their first child was born and Maria Barbara's elder, unmarried sister joined them. She remained to help run the household until her death in 1729.

Bach's time in Weimar was the start of a sustained period of composing keyboard and orchestral works. He attained the proficiency and confidence to extend the prevailing structures and to include influences from abroad. He learned to write dramatic openings and employ the dynamic motor - rhythms and harmonic schemes found in the music of Italians such as Vivaldi, Corelli and Torelli. Bach absorbed these stylistic aspects in part by transcribing Vivaldi's string and wind concertos for harpsichord and organ; many of these transcribed works are still played in concert often. Bach was particularly attracted to the Italian style in which one or more solo instruments alternate section - by - section with the full orchestra throughout a movement.

In Weimar, Bach continued to play and compose for the organ, and to perform concert music with the duke's ensemble. He also began to write the preludes and fugues which were later assembled into his monumental work Das Wohltemperierte Clavier ("The Well - Tempered Clavier" — Clavier meaning clavichord or harpsichord), consisting of two books, compiled in 1722 and 1744, each containing a prelude and fugue in every major and minor key.

Also in Weimar Bach started work on the Little Organ Book for his eldest son, Wilhelm Friedemann, containing traditional Lutheran chorales (hymn tunes) set in complex textures to train organists. In 1713 Bach was offered a post in Halle when he advised the authorities during a renovation by Christoph Cuntzius of the main organ in the west gallery of the Marktkirche Unser Lieben Frauen. Johann Kuhnau and Bach played again when it was inaugurated in 1716. Musicologists debate whether his first Christmas cantata Christen, ätzet diesen Tag, BWV 63, was premiered here in 1713, or if it was performed for the bicentennial of the Reformation in 1717. Bach eventually fell out of favor in Weimar and was, according to a translation of the court secretary's report, jailed for almost a month before being unfavorably dismissed:

Leopold, Prince of Anhalt - Köthen hired Bach to serve as his Kapellmeister (director of music) in 1717. Prince Leopold, himself a musician, appreciated Bach's talents, paid him well, and gave him considerable latitude in composing and performing. The prince was Calvinist and did not use elaborate music in his worship; accordingly, most of Bach's work from this period was secular, including the Orchestral Suites, the Six Suites for Unaccompanied Cello, the Sonatas and Partitas for Solo Violin and the Brandenburg Concertos. Bach also composed secular cantatas for the court such as the Die Zeit, die Tag und Jahre macht, BWV 134a.

Despite being born in the same year and only about 80 miles apart, Bach and Handel never met. In 1719 Bach made the 20 mile journey from Köthen to Halle with the intention of meeting Handel, however Handel had recently departed the city. In 1730, Bach's son Friedmann traveled to Halle to invite Handel to visit the Bach family in Leipzig, however the visit did not eventuate.

On 7 July 1720, while Bach was abroad with Prince Leopold, Bach's first wife suddenly died. The following year, he met Anna Magdalena Wilcke, a young, highly gifted soprano 17 years younger than he was who performed at the court in Köthen; they married on 3 December 1721. Together they had 13 more children, six of whom survived into adulthood: Gottfried Heinrich, Johann Christoph Friedrich and Johann Christian, all of whom became significant musicians; Elisabeth Juliane Friederica (1726-81), who married Bach's pupil Johann Christoph Altnikol; Johanna Carolina (1737-81); and Regina Susanna (1742-1809).

In 1723, Bach was appointed Cantor of the Thomasschule at Thomaskirche in Leipzig, and Director of Music in the principal churches in the town, namely the Nikolaikirche and the Paulinerkirche, the church of the University of Leipzig. This was a prestigious post in the mercantile city in the Electorate of Saxony, which he held for 27 years until his death. It brought him into contact with the political machinations of his employer, Leipzig's city council.

Bach was required to instruct the students of the Thomasschule in singing and to provide church music for the main churches in Leipzig. Bach was required to teach Latin, but he was allowed to employ a deputy to do this instead. A cantata was required for the church service on Sundays and additional church holidays during the liturgical year. He usually performed his own cantatas, most of which were composed during his first three years in Leipzig. The first of these was Die Elenden sollen essen, BWV 75, first performed in the Nikolaikirche on 30 May 1723, the first Sunday after Trinity. Bach collected his cantatas in annual cycles. Five are mentioned in obituaries, three are extant. Most of these concerted works expound on the Gospel readings prescribed for every Sunday and feast day in the Lutheran year. Bach started a second annual cycle the first Sunday after Trinity of 1724, and composed only Chorale cantatas, each based on a single church hymn. These include O Ewigkeit, du Donnerwort, BWV 20, Wachet auf, ruft uns die Stimme, BWV 140, Nun komm, der Heiden Heiland, BWV 62, and Wie schön leuchtet der Morgenstern, BWV 1.

Bach drew the soprano and alto choristers from the School, and the tenors and basses from the School and elsewhere in Leipzig. Performing at weddings and funerals provided extra income for these groups; it was probably for this purpose, and for in-school training, that he wrote at least six motets, at least five of which are for double choir. As part of his regular church work, he performed other composers' motets, which served as formal models for his own.

Bach broadened his composing and performing beyond the liturgy by taking over, in March 1729, the directorship of the Collegium Musicum, a secular performance ensemble started by the composer Georg Philipp Telemann. This was one of the dozens of private societies in the major German-speaking cities that was established by musically active university students; these societies had become increasingly important in public musical life and were typically led by the most prominent professionals in a city. In the words of Christoph Wolff, assuming the directorship was a shrewd move that "consolidated Bach's firm grip on Leipzig's principal musical institutions". Year round, the Leipzig's Collegium Musicum performed regularly in venues such as the Zimmermannsches Caffeehaus, a Coffeehouse on Catherine Street off the main market square. Many of Bach's works during the 1730s and 1740s were written for and performed by the Collegium Musicum; among these were parts of his Clavier - Übung (Keyboard Practice) and many of his violin and harpsichord concertos.

In 1733, Bach composed the Kyrie and Gloria of the Mass in B minor. He presented the manuscript to the King of Poland, Grand Duke of Lithuania and Elector of Saxony, August III in an eventually successful bid to persuade the monarch to appoint him as Royal Court Composer. He later extended this work into a full Mass, by adding a Credo, Sanctus and Agnus Dei, the music for which was almost wholly taken from his own cantatas. Bach's appointment as court composer was part of his long term struggle to achieve greater bargaining power with the Leipzig Council. Although the complete mass was probably never performed during the composer's lifetime, it is considered to be among the greatest choral works of all time. Between 1737 and 1739, Bach's former pupil Carl Gotthelf Gerlach took over the directorship of the Collegium Musicum.

In 1747, Bach visited the court of King Frederick II of Prussia at Potsdam. The king played a theme for Bach and challenged him to improvise a fugue based on his theme. Bach improvised a three-part fugue on Frederick's pianoforte, then a novelty, and later presented the king with a Musical Offering which consists of fugues, canons and a trio based on this theme. Its six - part fugue includes a slightly altered subject more suitable for extensive elaboration.

In the same year Bach joined the Correspondierende Societät der musicalischen Wissenschaften of Lorenz Christoph Mizler after a long formal preparation which was necessary by the Society. Mizler called his former teacher one of his “guten Freunde und Gönner” (good friends and sponsors). This is particularly noteworthy because Mizler was a passionate representative of the German and Polish Enlightenment. Bach's membership had several effects. On the occasion of his entry to this Society Bach composed Einige canonische Veraenderungen, / über das / Weynacht - Lied: / Vom Himmel hoch da / komm ich her (BWV 769). In 1746, during the preparation of Bach's entry, the famous Bach portrait was painted by Elias Gottlob Haussmann. A portrait had to be submitted by each member of the Society. The canon triplex á 6 voc. (BWV 1076) on this portrait was dedicated to the Society. The Society insisted on a necrology of each member. Therefore, Mizler initiated the history of the Bach biographies in the Musikalische Bibliothek. It was often argued, that other late works might have a connection with the music theory based Society. One of those works was The Art of Fugue, which was composed shortly before his death, but Bach never completed the final fugue. It consists of 18 complex fugues and canons based on a simple theme. It was only published posthumously in 1751.

The final work Bach completed was a chorale prelude for organ, entitled Vor deinen Thron tret ich hiermit (Before thy throne I now appear, BWV 668a) which he dictated to his son - in - law, Johann Altnikol, from his deathbed. When the notes on the three staves of the final cadence are counted and mapped onto the Roman alphabet, the initials "JSB" are found.

Bach's health declined in 1749; on 2 June, Heinrich von Brühl wrote to one of the Leipzig burgomasters to request that his music director, Gottlob Harrer, fill the Thomascantor and Director musices posts "upon the eventual ... decease of Mr. Bach." Bach became increasingly blind, so the British eye surgeon John Taylor operated on Bach while visiting Leipzig in March or April 1750.

On 28 July 1750 Bach died at the age of 65. A contemporary newspaper reported "the unhappy consequences of the very unsuccessful eye operation" as the cause of death. Modern historians speculate that the cause of death was a stroke complicated by pneumonia. His son Emanuel and his pupil Johann Friedrich Agricola wrote an obituary of Bach.

Bach's estate included five Clavecins, two lute - harpsichords, three violins, three violas, two cellos, a viola da gamba, a lute and a spinet, and 52 "sacred books", including books by Martin Luther and Josephus. He was originally buried at Old St. John's Cemetery in Leipzig. His grave went unmarked for nearly 150 years. In 1894 his coffin was finally found and moved to a vault in St. John's Church. This building was destroyed by Allied bombing during World War II, so in 1950 Bach's remains were taken to their present grave at Leipzig's Church of St. Thomas.

A detailed obituary of Bach was published (without attribution) four years later in 1754 by Lorenz Christoph Mizler (a former student) in Musikalische Bibliothek, a music periodical. The obituary remains probably "the richest and most trustworthy" early source document about Bach. After his death, Bach's reputation as a composer at first declined; his work was regarded as old fashioned compared to the emerging classical style. Initially he was remembered more as a player and teacher.

During the late eighteenth and early nineteenth century, Bach was widely recognized for his keyboard work. Mozart, Beethoven, Chopin, Robert Schumann and Felix Mendelssohn were among his most prominent admirers; they began writing in a more contrapuntal style after being exposed to Bach's music. Beethoven described him as the "Urvater der Harmonie", "original father of harmony".

Bach's reputation among the wider public was enhanced in part by Johann Nikolaus Forkel's 1802 biography of Bach. Felix Mendelssohn significantly contributed to the revival of Bach's reputation with his 1829 Berlin performance of the St Matthew Passion. In 1850, the Bach Gesellschaft (Bach Society) was founded to promote the works; in 1899 the Society published a comprehensive edition of the composer's works with little editorial intervention.

During the 20th century, the process of recognizing the musical as well as the pedagogic value of some of the works continued, perhaps most notably in the promotion of the Cello Suites by Pablo Casals, the first major performer to record these suites. Another development has been the growth of the "authentic" or "period performance" movement, which attempts to present music as the composer intended it. Examples include the playing of keyboard works on harpsichord rather than modern grand piano and the use of small choirs or single voices instead of the larger forces favored by 19th and early 20th century performers.

Bach's music is frequently bracketed with the literature of William Shakespeare and the teachings of Isaac Newton. In Germany, during the twentieth century, many streets were named and statues were erected in honour of Bach. His music features three times – more than any other composer – on the Voyager Golden Record, a phonograph record containing a broad sample of the images, common sounds, languages, and music of Earth, sent into outer space with the two Voyager probes.

In 1950, a thematic catalogue called Bach Werke Verzeichnis (Bach Works Catalogue) was compiled by Wolfgang Schmieder. Schmieder largely followed the Bach Gesellschaft Ausgabe, a comprehensive edition of the composer's works that was produced between 1850 and 1905: BWV 1-224 are cantatas; BWV 225-249, large scale choral works including his Passions; BWV 250-524, chorales and sacred songs; BWV 525-748, organ works; BWV 772-994, other keyboard works; BWV 995-1000, lute music; BWV 1001-40, chamber music; BWV 1041-71, orchestral music; and BWV 1072-1126, canons and fugues.

Bach was best known during his lifetime as an organist, organ consultant, and composer of organ works in both the traditional German free genres — such as preludes, fantasias and toccatas — and stricter forms, such as chorale preludes and fugues. At a young age, he established a reputation for his great creativity and ability to integrate foreign styles into his organ works. A decidedly North German influence was exerted by Georg Böhm, with whom Bach came into contact in Lüneburg, and Dieterich Buxtehude, whom the young organist visited in Lübeck in 1704 on an extended leave of absence from his job in Arnstadt. Around this time, Bach copied the works of numerous French and Italian composers to gain insights into their compositional languages, and later arranged violin concertos by Vivaldi and others for organ and harpsichord. During his most productive period (1708-14) he composed several pairs of preludes and fugues and toccatas and fugues, and the Orgelbüchlein ("Little organ book"), an unfinished collection of 46 short chorale preludes that demonstrates compositional techniques in the setting of chorale tunes. After leaving Weimar, Bach wrote less for organ, although his best known works (the six trio sonatas, the "German Organ Mass" in Clavier - Übung III from 1739, and the Great Eighteen chorales, revised late in his life) were all composed after his leaving Weimar. Bach was extensively engaged later in his life in consulting on organ projects, testing newly built organs, and dedicating organs in afternoon recitals.

Bach wrote many works for harpsichord, some of which may have been played on the clavichord. Many of his keyboard works are anthologies that encompass whole theoretical systems in an encyclopedic fashion.

• The Well - Tempered Clavier, Books 1 and 2 (BWV 846-893). Each book consists of a prelude and fugue in each of the 24 major and minor keys in chromatic order from C major to B minor (thus, the whole collection is often referred to as 'the 48'). "Well - tempered" in the title refers to the temperament (system of tuning); many temperaments before Bach's time were not flexible enough to allow compositions to utilise more than just a few keys.
• The 15 Inventions and 15 Sinfonias (BWV 772-801). These short two- and three - part contrapuntal works are arranged in the same chromatic order as the Well - Tempered Clavier, omitting some of the rarer keys. These pieces were intended by Bach for instructional purposes.
• Three collections of dance suites: the English Suites (BWV 806-811), the French Suites (BWV 812-817), and the Partitas for keyboard (BWV 825-830). Each collection contains six suites built on the standard model (Allemande – Courante – Sarabande – (optional movement) – Gigue). The English Suites closely follow the traditional model, adding a prelude before the allemande and including a single movement between the sarabande and the gigue. The French Suites omit preludes, but have multiple movements between the sarabande and the gigue. The partitas expand the model further with elaborate introductory movements and miscellaneous movements between the basic elements of the model.
• The Goldberg Variations (BWV 988), an aria with thirty variations. The collection has a complex and unconventional structure: the variations build on the bass line of the aria, rather than its melody and musical canons are interpolated according to a grand plan. There are nine canons within the 30 variations, one every three variations between variations 3 and 27. These variations move in order from canon at the unison to canon at the ninth. The first eight are in pairs (unison and octave, second and seventh, third and sixth, fourth and fifth). The ninth canon stands on its own due to compositional dissimilarities.
• Miscellaneous pieces such as the Overture in the French Style (French Overture, BWV 831), Chromatic Fantasia and Fugue (BWV 903), and the Italian Concerto (BWV 971).

Among Bach's lesser known keyboard works are seven toccatas (BWV 910-916), four duets (BWV 802-805), sonatas for keyboard (BWV 963-967), the Six Little Preludes (BWV 933-938) and the Aria variata alla maniera italiana (BWV 989).

Bach wrote for single instruments, duets, and small ensembles. Many of his solo works, such as his six sonatas and partitas for violin (BWV 1001-1006), six cello suites (BWV 1007-1012) and Partita for solo flute (BWV 1013), are among the most profound works in the repertoire. Bach composed a suite and several other works for solo lute. He wrote trio sonatas; solo sonatas (accompanied by continuo) for the flute and for the viola da gamba; and a large number of canons and ricercare, mostly with unspecified instrumentation. The most significant examples of the latter are contained in The Art of Fugue and The Musical Offering.

Bach's best known orchestral works are the Brandenburg Concertos, so named because he submitted them in the hope of gaining employment from Margrave Christian Ludwig of Brandenburg - Schwedt in 1721; his application was unsuccessful. These works are examples of the concerto grosso genre. Other surviving works in the concerto form include two violin concertos (BWV 1041 and BWV 1042); a Concerto for Two Violins in D Minor (BWV 1043), often referred to as Bach's "double" concerto; and concertos for one to four harpsichords. It is widely accepted that many of the harpsichord concertos were not original works, but arrangements of his concertos for other instruments now lost. A number of violin, oboe and flute concertos have been reconstructed from these. In addition to concertos, Bach wrote four orchestral suites, and a series of stylized dances for orchestra, each preceded by a French overture.

As the Thomaskantor, beginning mid of 1723, Bach performed a cantata each Sunday and feast day that corresponded to the lectionary readings of the week. Although Bach performed cantatas by other composers, he composed at least three entire annual cycles of cantatas at Leipzig, in addition to those composed at Mühlhausen and Weimar. In total he wrote more than 300 sacred cantatas, of which approximately 200 survive.

His cantatas vary greatly in form and instrumentation, including those for solo singers, single choruses, small instrumental groups, or grand orchestras. Many consist of a large opening chorus followed by one or more recitative - aria pairs for soloists (or duets) and a concluding chorale. The recitative is part of the corresponding Bible reading for the week and the aria is a contemporary reflection on it. The melody of the concluding chorale often appears as a cantus firmus in the opening movement. Among his best known cantatas are:

• Christ lag in Todes Banden, BWV 4
• Ich hatte viel Bekümmernis, BWV 21
• Ein feste Burg ist unser Gott, BWV 80
• Gottes Zeit ist die allerbeste Zeit, BWV 106 (Actus Tragicus)
• Wachet auf, ruft uns die Stimme, BWV 140
• Herz und Mund und Tat und Leben, BWV 147

In addition, Bach wrote a number of secular cantatas, usually for civic events such as council inaugurations. These include wedding cantatas, the Wedding Quodlibet, the Peasant Cantata and the Coffee Cantata.

Bach's large choral - orchestral works include the grand scale St Matthew Passion and St John Passion, both written for Good Friday vespers services at the Thomaskirche and the Nikolaikirche in alternate years, and the Christmas Oratorio (a set of six cantatas for use in the Liturgical season of Christmas). The two versions of the Magnificat (one in E-flat major, with four interpolated Christmas related movements, and the later and better known version in D major), the Easter Oratorio, and the Ascension Oratorio are smaller and simpler than the Passions and the Christmas Oratorio.

Bach assembled his other large work, the Mass in B minor, near the end of his life, mostly from pieces composed earlier (such as the cantatas Gloria in excelsis Deo, BWV 191 and Weinen, Klagen, Sorgen, Zagen, BWV 12). The mass was never performed in full during Bach's lifetime. All of these movements, unlike the six motets (Singet dem Herrn ein neues Lied; Der Geist hilft unsrer Schwachheit auf, BWV 226; Jesu, meine Freude; Fürchte dich nicht; Komm, Jesu, komm!; and Lobet den Herrn alle Heiden), have substantial solo parts as well as choruses.

Bach's musical style arose from his skill in contrapuntal invention and motivic control, his flair for improvisation, his exposure to North and South German, Italian and French music, and his devotion to the Lutheran liturgy. His access to musicians, scores and instruments as a child and a young man and his emerging talent for writing tightly woven music of powerful sonority, allowed him to develop an eclectic, energetic musical style in which foreign influences were combined with an intensified version of the pre-existing German musical language. From the period 1713-14 onward he learned much from the style of the Italians.

During the Baroque period, many composers only wrote the framework, and performers embellished this framework with ornaments and other elaboration. This practice varied considerably between the schools of European music; Bach notated most or all of the details of his melodic lines, leaving little for performers to interpolate. This accounted for his control over the dense contrapuntal textures that he favored, and decreased leeway for spontaneous variation of musical lines. At the same time, Bach left the instrumentation of major works includingThe Art of Fugue open.

Bach's devout relationship with the Christian God in the Lutheran tradition and the high demand for religious music of his times placed sacred music at the center of his repertory. He taught Luther's Small Catechism as the Thomascantor in Leipzig, and some of his pieces represent it; the Lutheran chorale hymn tune was the basis of much of his work. He wrote more cogent, tightly integrated chorale preludes than most. The large scale structure of some of Bach's sacred works is evidence of subtle, elaborate planning. For example, the St Matthew Passion illustrates the Passion with Bible text reflected in recitatives, arias, choruses and chorales. The structure of the Easter Oratorio, BWV 249, resembles The Crucifixion.

Bach's drive to display musical achievements was evident in his composition. He wrote much for the keyboard and led its elevation from continuo to solo instrument with harpsichord concertos and keyboard obbligato. Virtuosity is a key element in other pieces, such as the Prelude and Fugue in E minor, BWV 548 for organ in which virtuosic passages are mapped onto alternating flute and reed solos within the fugal development.

Bach produced collections of movements that explored the range of artistic and technical possibilities inherent in various genres. The most famous example is the Well Tempered Clavier, in which each book presents a prelude and fugue in every major and minor key. Each fugue displays a variety of contrapuntal and fugal techniques.

Present day Bach performers usually pursue one of two traditions: so-called "authentic performance practice", utilizing historical techniques; or the use of modern instruments and playing techniques, often with larger ensembles. In Bach's time orchestras and choirs were usually smaller than those of later composers, and even Bach's most ambitious choral works, such as his Mass in B minor and Passions, were composed for relatively modest forces. Some of Bach's important chamber music does not indicate instrumentation, which allows for a greater variety of ensembles.

Easy listening realizations of Bach's music and their use in advertising contributed greatly to Bach's popularization in the second half of the twentieth century. Among these were the Swingle Singers' versions of Bach pieces that are now well known (for instance, the Air on the G string, or the Wachet Auf chorale prelude) and Wendy Carlos' 1968 Switched-On Bach, which used the Moog electronic synthesiser. Jazz musicians have adopted Bach's music, with Jacques Loussier, Ian Anderson, Uri Caine and the Modern Jazz Quartet among those creating jazz versions of Bach works.