Dave Massey looks at one of classical music's giants, JOHANN SEBASTIAN BACH.

When he was 15 be obtained a post in the choir at the Church of St Michael at Luneburg, but his voice soon broke and he stayed on as rehearsal accompanist, occasional violinist, and member of one of the town bands. He was now, in fact, a professional musician. When he was 18 he was offered a post at Weimar, as one of the musicians of the brother of the reigning Duke, and a few months later a better post as organist at Arnstadt. Then, in 1707, he moved again - this time to Muhlhausen as organist. In the same year he married his cousin, Maria Barbara.

After a year at Muhlhausen Bach returned to Weimar, this time as court organist and chamber musician to the Duke himself. He now had the opportunity to compose a great deal of organ music, and later, after promotion, music for the Duke's chapel.

He spent nine years at Weimar and then, in 1717, moved on the court of Prince Leopold of Anhalt-Cothen, who was himself an excellent amateur musician. Here Bach acted as 'Kapelmeister'; he had the direction of all the prince's singers and instrumentalists, and was therefore encouraged to write a great deal of music for the orchestra.

He remained at Cothen for six years, during which time his wife died and a year later (1721) he married again. Prince Leopold married in the same year, but his bride had no taste for music, and Bach began to look for a new post.

He was 38 when he moved to Leipzig (1723). After all his wanderings he had finally come to rest, and here, as 'Cantor' of the ancient St Thomas School, he stayed until his death 27 years later.

Altogether he wrote five complete sets (295) of Church Cantatas, each containing a cantata for every Sunday in the church's year. About two hundred of these have survived.

He also composed a Christmas Oratorio and some wonderful settings of the 'Passion' (that is to say, the story of Christ's crucifixion). Two of these Passions remain: the great St Matthew Passion and the St John Passion; and together with the Mass in B minor they contain some of his finest music.

At the end of his life Bach became blind - as did his contemporary Handel. His death attracted little attention and his widow was left to live out her life in great poverty: she died in 1760, aged 59, and was given a pauper's funeral.