‘Among the old musicians it used to be customary to write a mere outline or suggestion of the voice part. Particularly was this the case when there was a return to the original theme, while it applied equally to the conventional ending found in nearly all arie of that time. The singers were expected to elaborate the simple melody given them, and to raise upon this foundation a graceful edifice, adorned with what ornaments their individual taste dictated, and suited to their own powers of execution.
The following illustration will prove the truth of the above assertion. It is a story from the lips of the maestro (Manuel Garcia.)
While his father, the elder Garcia, was at Naples, one of the old Italian composers came to produce a new opera.
At the opening rehearsal the tenor was given his part to read at sight. When his first aria had been reached he sang it off with perfect phrasing and feeling, but exactly note for note as written. After he had finished the composer said, "Thank you, signer, very nice, but that was not at all what I wanted." He asked for an explanation, and was informed that the melody which had been written down was intended merely as a skeleton which the singer should clothe with whatever his imagination and artistic instinct prompted. The writer of the music asked him to go through it again, and this time to treat it exactly as though it were his own composition.
The elder Garcia was skilful at improvising: consequently, in giving the aria for the second time, he made a number of alterations and additions, introducing runs, trills, roulades, and cadenzas, all of which were performed with the most brilliant execution. This time, when the end of the music was reached, the old composer shook him warmly by the hand. "Bravo! Magnificent! That was my music, as I wished it to be given."’
Malcolm Sterling Mackinlay, Garcia the Centenarian and His Times (Edinburgh: Blackwood, 1908). p.34
The image below was painted in 1877 by Louis Béroud and is entitled ‘L’escalier de l’opéra Garnier.’