when:Beethoven performed parts of it in his 1808 concert featuring the premieres of four major works including his Fifth Symphony.

why:Following his return from England in 1795, Haydn had composed one mass per year for the Esterházy family, to celebrate the name day of the Prince's wife. ... Beethoven was fully aware of the tradition that Haydn had established and it influenced him strongly in writing the Mass in C major.

for:Ludwig van Beethoven composed the Mass in C major, Op. 86, to a commission from Prince Nikolaus Esterházy II in 1807. The mass, scored for four vocal soloists, choir and orchestra, was premiered that year by the Prince's musical forces in Eisenstadt.86, to a commission from Prince Nikolaus Esterházy II in 1807. The mass, scored for four vocal soloists, choir and orchestra, was premiered that year by the Prince's musical forces in Eisenstadt.

The full name of Beethoven is

Ludwig van Beethoven