A Portrait of Bach in Old Age, known as the Altersbild. A man of deep Lutheran faith, Bach’s music was an expression of his religious convictions. His well-known works include the Brandenburg Concertos, the Goldbert Variations, 300 cantatas, two Passions, the Mass in B Minor and two volumes of The Well-Tempered Clavier. In his lifetime he was best known as an organist, and other members of his musical family, including his son Carl Philipp Emmanuel, were more famous for their compositions – until the early 19th century, when J.S. came to be recognized as the greatest Bach of all.