[3] After achieving the rank of Feldzeugmeister Nikolaus quit the army for diplomacy and was employed as extraordinary ambassador on several important occasions.

Napoleon, having just defeated the Austrian armies and occupied Vienna, sought to weaken the Habsburg monarchy by severing its Hungarian territories.

Faithful to the Esterházy tradition of loyalty to their Emperor, Nikolaus refused the offer, and indeed he went further and raised a regiment of volunteers to help defend the Empire, an action he had previously taken in 1797.

[9] The redesigned gardens included extensive greenhouses, intended both to support landscaping and to house a large collection of plants, which by 1820 had grown to 60,000 varieties.

[10] In 1820, Esterházy was honoured by Austrian-Czech botanist, zoologist and entomologist, Johann Christian Mikan who named a plant species from South America after him, Esterhazya.

[11][12] The prince was at least at some level a musician (a portrait of him by Fischer shows him playing the clarinet)[13] and he spent some of his wealth as a patron of music.

[a] Nikolaus persuaded Joseph Haydn to return as active (though part-time) Kapellmeister, and gradually built up the Chor musique, his group of instrumentalists and singers: 15 in 1796, 29 by 1802.

[14] These musical forces, augmented by occasional extras, premiered several major works, notably the six masses composed by Haydn, some in celebration of the name day of Nikolaus's wife Maria Hermenegild.

During Haydn's long period of infirmity (roughly 1803 to his death in 1809), the Prince was very supportive, increasing his pension to compensate for inflation (1806) and covering his medical expenses.

Nikolaus later wrote to Countess Henriette Zielinska, "Beethoven's music is unbearably ridiculous and detestable; I am not convinced it can ever be performed properly.

[19] According to Mraz, Nikolaus "coped poorly" with the very high inflation that arose in the Austrian Empire as the result of the Napoleonic Wars.

He continued to spend freely both on art works and on his brothel, and ultimately the law intervened, subjecting him to a sequestration order (1832).

[20] Haydn biographer Karl Geiringer describes Nikolaus II thus: "He was as complete an autocrat as his grandfather had been, but lacked the latter's charm, kindliness, and genuine understanding of music .