Johann Sebastian Bach (March 21, 1685 - July 28, 1750) was a German Baroque composer. He is generally ranked among history's greatest and most influential composers. His compositions often embody profound intellectual depth, emotional power, and technical command.
(Public domain image from Pratt's History of Music, 1907 full size image)
Bach is especially noted for his complex and ingenious contrapuntal writing; more than any other composer, Bach is associated with the fugue. The best known example of his fugal writing is probably The Well-Tempered Clavier, which comprises 48 preludes and fugues, two for each major and minor key. Another work with much fugal writing is The Art of Fugue, which was incomplete when Bach died. There are 14 fugues (called Contrapuncti by Bach), all based on the same theme.
Bach wrote much of his music for the Lutheran Church; in particular, his many cantatas were composed for normal Sunday services, and the St. John Passion and St. Matthew Passion were composed for special services on Good Friday.
His family life was substantial. Of the 13 children his wife bore him, several survived to become respected composers in their own right: most notably C.P.E. Bach, who was very well regarded by Mozart. The trust Johan Sebastian placed in one of his elder sons (Johan Christian?) was ill-fated; he forever lost several Passions, inter alia, left behind by his father that could have been the equal of the St. Matthew & St. John. Were it not for C.P.E.'s faithful stewardship of his father's manuscripts, the world may never have known J.S. In more ways than one, Bach's music was elevated by family collaboration.
Other famous works by Bach include Brandenburg Concerti, Mass in B Minor, and the 4 Orchestral Suites.