Background

In 1733 Bach sought to advance his status at Leipzig by petitioning Friedrich August, the Elector of Saxony, for a court title, submitting as proof of his skill the Kyrie and Gloria of a Lutheran mass.  Some 3 years later, he was appointed the "Royal Court Composer". Although Bach was a Lutheran (Protestant), he was working for a Catholic court and over subsequent years, he completed the Mass by adding the Roman rite sections of Credo, Sanctus/Osanna/Benedictus, Agnus Dei/Dona nobis pacem, largely with music "parodied" from earlier cantata movements. There is no agreement amongst researchers as to when these latter parts were written – The Credo might have been written in 1732, or 1742 or 1745. The final three section date from the late 1740s. The earlier sections could date back to 1724.

The different sections call for different numbers and arrangements of performers, suggesting that Bach never expect the work to be performed in its entirety. In fact, there is no evidence that the Mass was performed in Bach's lifetime. It is thought that he regarded it as an exemplar of his mastery in all the main sacred genres of his time.

The Mass in B Minor is widely regarded as one of the supreme achievements of "classical" music. Alberto Basso summarises the work as follows: "The Mass in B minor is the consecration of a whole life: started in 1733 for 'diplomatic' reasons, it was finished in the very last years of Bach's life, when he had already gone blind. This monumental work is a synthesis of every stylistic and technical contribution the Cantor of Leipzig made to music. But it is also the most astounding spiritual encounter between the worlds of Catholic glorification and the Lutheran cult of the cross."

Bach scholar Christoph Wolff describes the work as representing "a summary of his writing for voice, not only in its variety of styles, compositional devices, and range of sonorities, but also in its high level of technical polish...Bach's mighty setting preserved the musical and artistic creed of its creator for posterity."

Oxford Companion to Music and Wikipedia are both acknowledged.