He brought the art of polyphonic writing to its highest and most sublime point. His value to the student cannot be exaggerated, for he is the musical Bible to all who would be musicians.
The organ was the core of his musical thinking and it is in the things which center about the organ that his art is loftiest.
Although he was most ingenious in writing counterpoint, he was never dry and tricky as were other writers. His subjects were always original and his melodic line always of rare beauty.
His works are most varied: fugues, motets, cantatas, passions, oratorios, concertos, sonatas and suites. He was a radical in his day, for he threw over conventional notions of harmony as to proper keys and insisted upon a new system of tuning the clavier, so as to use the whole range of tones. The “Well-tempered Clavichord,” two groups of 24 Preludes and Fugues in 24 keys, was the outcome of this. It was so called because it was written to show the possibilities of a clavier (or clavichord) tuned according to an idea of his, enabling one to play in all keys. This was one of the greatest discoveries in the whole story of music, for it made possible all the music which has followed. The keyboard was divided into equal half-steps. This made twelve half-steps within each octave and thus all the intervals became fixed, and modulation from key to key was possible. Heretofore, if one went from one key to another, the instrument sounded out of tune, but now instruments were tuned, as we glibly say, “to scale.”
He invented a new fingering in which the thumb and little finger were used for the first time. We wonder why the thumb had been snubbed!
The pianoforte was just coming into prominence in Bach’s day but he preferred the clavier, on which he felt he could play with more expression.
He developed the fugue to its highest point. A fugue is an enlarged canon in which the fragments of theme or melody are taken up and answered by two, or more, voices. One voice declares the subject and the answer is repeated usually in the dominant key a fifth above, while the first voice gives the counter-subject. There are various kinds of fugues, depending on their construction. After the voices have all entered, separated sometimes by little passages called “episodes,” a section in which the subject is freely developed comes, and then the stretto, in which all the parts enter racing and overlapping, building up to a climax; then follows the cadence or ending.
To write a noble or lofty fugue, neither dry nor pedantic, takes art to the nth power! Bach had the art that touched Heaven’s borders! In truth you can safely divide fugues into two classes—Bach’s and all others!
None of Bach’s works were published until he was forty years old, and most of them not until long after his death, and many of his manuscripts were lost and never published at all.
The list of his works is stupendous; the Bach Gesellschaft (Bach Society, 1850) published them in sixty volumes! Among them were the 48 Preludes and Fugues (The Well-tempered Clavichord Collection); 12 Suites; many Inventions in 2 and 3 parts; partitas; 12 concertos for 1, 2, 3 and 4 claviers with orchestra; many sonatas and concertos for violin, flute, viola da gamba, clavier, and orchestra; several overtures for orchestras; vocal works; 200 motets and cantatas; 5 Passions, of which the greatest are the St. Matthew and the St. John; 5 masses of which his B Minor Mass is a world masterpiece; oratorios; magnificats; many organ works, and old German chorales harmonized for voices.