The notes of a parley do not appear to exist.
[Perhaps a little light may be got out of the symphony to Purcell's duet in King Arthur, 'Sound a Parley ye fair.']
In the text, the word is used several times. In three cases, John II, i, 205, 226 and H. 5. III, iii, 2, 'the parle' means the conference of the parties itself, not the trumpet call summoning them. In the rest, 'parle' or 'parley' simply means the sound of the trumpet, as explained above. H. 6. B. IV, viii, 4; R. 2. I, i, 192, III, iii, 33; H. 6. C. V, i, 16; Othello II, iii, 23.
Horns, or Horns wind a peal, or Horns winded.
This is very rare. Seven times in only four plays, one of which is the doubtful Titus Andronicus.
Three times it is used of hunting horns, Titus II, ii, and Id. l. 10, and in the Induction of the Taming of the Shrew; twice as a part of Lear's lessened state, Lear I, iii and I, iv; once announcing the Post from England, H. 6. C. III, iii; and once blown by Talbot as a military signal at the forcing of Auvergne Castle gates, H. 6. A. II, iii.
The 'peal' of horns referred to in Titus II, ii, 10 is a technical term in forestry for a particular set of notes on the horn. Méhul (1763-1817), in his overture 'Le jeune Henri,' introduces several old French hunting fanfares, which perhaps may give an idea of what was meant by 'Horns wind a peal.' [See [Appendix].] Also in Purcell's 'Dido and Eneas,' No. 16 (date 1675), in the scene between the Sorceress and the two witches who are plotting the destruction of 'Elissa,' at the words 'Hark! the cry comes on apace,' the violins give an imitation of a hunting call.
The only instance of the use of the word 'peal' in the text is in the same passage, Titus II, ii, 5, where Titus tells his hunters to 'ring a hunter's peal.' Here we have a last example of punning on a technical term of music.