H. C. Robbins Landon, Haydn's chief biographer, has described this mass as "arguably Haydn's greatest single composition".
Haydn's reputation was at its peak in 1798, but his world was in turmoil. Austria was under threat of invasion by Napoleon, and had been defeated in each of four major battles in less than a year. Haydn himself was exhausted after supervising the first performances of The Creation, completed a few months earlier; and his patron, Nicholas II, Prince Esterházy, had dismissed the wind section of his orchestra due to the financial instability engendered by the country's troubles. Haydn's original title for the piece, Missa in Angustiis, is Latin for 'Mass in Troubled Times'.
In May 1798, Napoleon Bonaparte invaded Egypt in an attempt to destroy Britain's trade routes to the East. Haydn didn't know it as he was composing the mass, but he and his audience found out around the time of its first performance that Napoleon had suffered a crushing defeat at the hands of the British fleet under Nelson's command, in the Battle of the Nile (1–3 August 1798). The mass gradually acquired the nickname Lord Nelson Mass, and the title became indelible in 1800 when Lord Nelson himself visited the Palais Esterházy, accompanied by his British mistress, Lady Emma Hamilton. They may even have heard the work performed.
This note is a précis of the Background section to Wikipedia's page on the Nelson Mass.
© Haydn Thompson 2021