The first known complete performance had been given in Leipzig by the Riedel-Verein on 10 April 1859. See
"Bach's Greatest Enigma - The Mass in B minor", BBC Radio 3, accessed 19 June 2011. Sections of the score had been given in Britain under conductors including John Hullah before 1876, but this was the first complete performance in Britain: see "Bach's Mass in B Minor", The Times, 11 May 1876, p. 5