"Shortly before the Coronation of the Emperor Leopold, and before Mozart received the commission to go to Prague, an unsigned letter was handed to him by an unknown messenger which, with many flattering remarks, contained the question whether Mozart would like to undertake the composition of a Requiem, for what price, and how soon he would be able to deliver it.
"Mozart, who was accustomed to take no step without consulting his wife, related to her this strange commission, and at the same time mentioned his desire to try his hand at this type of work too, the more so as the elevated and exalted style of church music was always close to his genius. She advised him to accept the commission. He therefore wrote to the unknown gentleman to say that he would write the Requiem for a certain sum; he could not exactly state the time he would require to complete it; but he would like to know the destination to which he was to deliver the work when it was finished. The same messenger shortly reappeared, bringing not only the agreed honorarium with him, but also the promise that, as he had been so reasonable in his price, he would receive a generous additional payment on handing over the work. He was moreover to write according to the mood and frame of his mind, but he was not to trouble to try and find out the name of his patron, for this search would certainly be in vain...."  

In 1877, Whistler showed eight works at the Grosvenor Gallery, including "Nocturne: Blue and Gold - Old Battersea Bridge," ... and "Nocturne in Black and Gold - The Falling Rocket" (The Detroit Institute of Arts, gift of Dexter M. Ferry). In Fors Clavigera, Ruskin wrote the following about the exhibition:

"Sir Coutts Lindsay ought not to have admitted works into the gallery in which the ill-educated conceit of the artist so nearly approached the aspect of wilful imposture. I have seen, and heard, much of Cockney impudence before now; but never expected to hear a coxcomb ask two hundred guineas for flinging a pot of paint in the public's face."

Ruskin's comments were reprinted in the Spectator, and Whistler sued for libel. The catalogue provides the following commentary:

"The case did not come to court until November 1878. Ruskin had had his first mental collapse in February that year, and did not appear. His instructions to his defence counsel were unrepentant: Whistler was ill-educated because the price demanded was unjust, the analogy between painting and music was misunderstood, the work was not art but ornament, unfinished and empty of ideas. No work should leave an artist's hands 'which his diligence could further complete, or his reflection further improve.'...Whistler dominated the trial with his witticisms, arguing the case for art for art's sake....Nocture...Old Battersea Bridge, which shows the profound influence of Japanese woodcuts on Whistler's art, was produced in court. Asked if it was a 'correct representation,' Whistler answered: 'It was not my intent simply to make a copy of Battersea Bridge. The pier in the centre of the picture may not be like the piers of Battersea Bridge. I did not intend to paint a portrait of Battersea Bridge, but only a painting of a moonlight scene. As to what the picture represents, that depends upon who looks at it.'...Whistler won, but the derisory award of a farthing's damages without costs led to his bankruptcy. Ruskin resigned his Slade Professorship, partly in disgust, partly because of his mental depression."