Though he was well known and admired by his contemporary colleagues as being a virtuous harpsichord and organ player, Johann Sebastian Bach is considered today one of the most important composers of all time. Born in a family of organ musicians and cantors settled in Turingia with a tradition of over 200 years of playing music, at the age of almost 10 years he becomes and orphan. Luckily, his big brother Johann Cristoph takes him under his wing and assumes responsibility of continuing little Johann Sebastian's musical education commenced by his father.
The Ohrdruf period (1695-1700) was the first step towards making acquaintance with two of what came to be his favorite instruments (the harpsichord and the church organ), under the severe guidance of Johann Cristoph. Due to his unusually pleasant soprano-like voice, he was received with open arms at the school from Lüneburg. In the years spent here (1700-1702), he was part of the choir and orchestral ensemble (as a violinist) and first came into contact with french instrumental music. Here he meets and gets aquainted with Georg Böhm and his music who was an organist for the Saint John church and who also introduces little Bach to the Hamburg area way of playing the organ.
Another important period in his life is the one spent at Mühlhausen (1707-1708) where he is hired as the town organist. Over 15 years, Johann Sebastian Bach worked at the princely residences as court organist and chamber music director - first in Weimar (1708-1717), and then in Köthen (1717-1723). In Weimar, his life was becoming better and better, his financial situation was improving and his double role as an organist and chamber ensemble director was only going to offer him more opportunities to perfect his skills as a composer and performer. Unfortunately, the injustice committed against him when, following the death of Drese, the court Kapellmeister (director of music), instead of Bach, is preferred Drese's son (an untalented musician). This lead Bach to resign from these roles.
Leopold, Prince of Anhalt-Köthen hired Bach to serve as his Kapellmeister - the highest rank given to a musician in the baroque period. Unlike Weimar, the prince from Köthen was passionate about music (he used to play the viola and sing, which made him pay a great deal of attention to musical entertainment - he even built a chapel).
Although he never fond of getting involved with the church again, after the death of Saint Thomas church in Leipzig (1722), Bach submits his application for the vacant job. In 1723 May 31st, Bach is officially confirmed as a cantor and, in the summer of the same year, he settles together with his family in the town in which he would later a series of remarkable pieces in the vocal-symphonic genre, such as: Magnificat, the Passions, Christmas Oratorio, Easter Oratorio, etc.
In the year of 1729 Bach takes leadership of the ”Collegium musicum”, a secular performance ensemble started by the composer Georg Philipp Telemann, who had an important role in the town's musical activity due to the organizing of regularly public concerts.
The fact that Bach studied both his contemporary colleagues and the ones that were before him, had great benefits on the development and the crystallization of his own unique style. It is very well known that he was attached to the music of the German-Danish composer Dietrich Buxtehude and of his ”rival” Georg Philipp Telemann. Also, the concerts and arias of Antonio Vivaldi or the compositions of Giovanni Palestrina, Arcangelo Corelli, Giovanni Battista Pergolesi, Girolamo Frescobaldi had a great influence on Bach's cantatas and Passions.
Bach has composed music in almost all musical genres of the era in which he lived. He didn't compose opera, although some episodes of his cantatas come close. As far as his vocal compositions go, also due to his duties towards the church, they exceed with a number of over 224 cantatas, 7 motets 12 liturgical pieces in latin, 6 oratorios, 189 coral works to which we add arias, secular cantatas and other compositions.
His interest for instrumental music manifested through a very large number of compositions for keyboard instruments: around 247 compositions for organ and 223 for harpsichord, the rest being composed for solo instruments like the violin (an instrument of which Bach was very fond of) or for orchestral ensembles.
Bach wasn't a genre creator or forms, instead he resumed the ones left heritage by his predecessors and he broadened them considerately on a both structural and expressive levels elevating them to a point of perfection never known before him.
Here you can find a list of all of Johann Sebastian Bach's compositions.