G. F. Handel -
The Ways of Zyon -
Funereal Cantata for the Death of Queen Caroline

The last picture in the video is a map to getting the Handel"s house in London.

That Handel´s composition was gotten by Mozart to creat the Introitus of his Requiem. Compare the chords sequence of the beggining, the motiv over the word "Requiem", the entrance of the winds in the first minute.