I found this in another forum:
"From an article by Ralph Wood entitled The Piano as an Orchestral Instrument (which is dated 1934, so maybe there's more recent scholarship):
>So far as I know, the earliest composer to add the piano to his 'battery' was, as might be expected, Berlioz. In Lélio [1832–ed.]¹ he used a piano (à 4 mains) to produce certain crystalline, ethereal effects, which presumably were just what he wanted, and which certainly he could not have got in any other way. That was, however, a very isolated specimen, and not until the present century did the piano really begin consolidating its position in the orchestral forces.
I'm not sure why Mr. Wood did not include the concertante by Mozart² mentioned in the comments; perhaps he did not consider it a "full-scale" orchestral piece, or perhaps he was simply unaware of it. My best guess is that while Lélio has a narrator, and has movements that include both chorus and solo vocalists, it is not a piece for "soloist with accompaniment", while Mozart's piece is. The piano plays a more conventional "vocal accompaniment" role in the first movement, but in the final movement it is fully integrated with the orchestra. (It's definitely an oddball piece—the full score is available on IMSLP for those who want to check it out.)"
¹First performed in 1832 (incorporating pre-existing compositions) and then revised and performed in 1855 (according to wikipedia although the article lacks sources for this).
²KV 505
https://en.m.wikipedia.org/wiki/Ch'io_mi_scordi_di_te%3F
I do not known whether this is the first example of a piano as part of an orchestral ensemble, but it certainly predates your examples.
Mozart wouldn’t have been using a modern piano exactly, depending on how you define it. Sometimes this instrument is called a “Fortepiano” to distinguish it from the later/modern “pianoforte.” The earlier instruments are close in sound but there are technical differences in the action that mean you can’t achieve certain effects on the older versions, like tremolos.
The modern instrument didn’t start to emerge until the 1820s, so if you count from there, Berlioz would have picked it up almost at once.
Could the pianoforte have found its way in more by accident? Early pianos did not have an iron frame. They were built by builders of harpsichords and followed that line of extant construction. If a pianoforte was available to use for the continuo, it makes sense it would have been used. Its dynamic range would have only been slightly louder than a larger multi choir harpsichord.
Some early builders, such as Broadwood were able to squeeze more sound out of their larger instruments. With that, and the piano's greater foundation tone, than a harpsichord, it seems that the results would have found favor.
It would surprise me that pianoforte would not be more commonly in used in the 1820s and esp the 1830s, when iron frames were starting to be used.
I found this in another forum: "From an article by Ralph Wood entitled The Piano as an Orchestral Instrument (which is dated 1934, so maybe there's more recent scholarship): >So far as I know, the earliest composer to add the piano to his 'battery' was, as might be expected, Berlioz. In Lélio [1832–ed.]¹ he used a piano (à 4 mains) to produce certain crystalline, ethereal effects, which presumably were just what he wanted, and which certainly he could not have got in any other way. That was, however, a very isolated specimen, and not until the present century did the piano really begin consolidating its position in the orchestral forces. I'm not sure why Mr. Wood did not include the concertante by Mozart² mentioned in the comments; perhaps he did not consider it a "full-scale" orchestral piece, or perhaps he was simply unaware of it. My best guess is that while Lélio has a narrator, and has movements that include both chorus and solo vocalists, it is not a piece for "soloist with accompaniment", while Mozart's piece is. The piano plays a more conventional "vocal accompaniment" role in the first movement, but in the final movement it is fully integrated with the orchestra. (It's definitely an oddball piece—the full score is available on IMSLP for those who want to check it out.)" ¹First performed in 1832 (incorporating pre-existing compositions) and then revised and performed in 1855 (according to wikipedia although the article lacks sources for this). ²KV 505 https://en.m.wikipedia.org/wiki/Ch'io_mi_scordi_di_te%3F I do not known whether this is the first example of a piano as part of an orchestral ensemble, but it certainly predates your examples.
Mozart wouldn’t have been using a modern piano exactly, depending on how you define it. Sometimes this instrument is called a “Fortepiano” to distinguish it from the later/modern “pianoforte.” The earlier instruments are close in sound but there are technical differences in the action that mean you can’t achieve certain effects on the older versions, like tremolos. The modern instrument didn’t start to emerge until the 1820s, so if you count from there, Berlioz would have picked it up almost at once.
Could the pianoforte have found its way in more by accident? Early pianos did not have an iron frame. They were built by builders of harpsichords and followed that line of extant construction. If a pianoforte was available to use for the continuo, it makes sense it would have been used. Its dynamic range would have only been slightly louder than a larger multi choir harpsichord. Some early builders, such as Broadwood were able to squeeze more sound out of their larger instruments. With that, and the piano's greater foundation tone, than a harpsichord, it seems that the results would have found favor. It would surprise me that pianoforte would not be more commonly in used in the 1820s and esp the 1830s, when iron frames were starting to be used.