Here we have a video of a historically-informed (or period) performance of Moonlight Sonata's first movement.

Wikipedia notes:

Some critics contest the methodology of the HIP movement, contending that its selection of practices and aesthetics are a product of the 20th century and that it is ultimately impossible to know what performances of an earlier time sounded like. Obviously, the older the style and repertoire, the greater the cultural distance and the increased possibility of misunderstanding the evidence. For this reason, the term "historically informed" is now preferred to "authentic", as it acknowledges the limitations of academic understanding, rather than implying absolute accuracy in recreating historical performance style, or worse, a moralising tone.

The impossibility of knowing what a historical performance sounds like seems to me to pose problems to normal (or inauthentic) performances too.

As I understand it, the third movement of the Moonlight Sonata is played rather differently on a modern piano due to how the notes sustain for longer. Presumably there are many other pieces where the same thing applies.

Who decides how such a historic piece is adjusted for modern instruments? Or do players learn to adjust themselves?

On a larger scale (i.e. an Orchestra) and with enough ambiguity, it seems that decisions might be made which drastically change a piece. Or that modern assumptions about a composer/period would overly-inform how a piece is played.

  • The video shows the first movement of the Moonlight Sonata. How is the third movement played differently on modern pianos as compared to contemporaneous instruments? – phoog Jan 22 at 20:59
  • @phoog Yeah I know, I only found that part. Take with a massive pinch of salt, but I remember that due the speed of notes in the third movement, some bits need to played with a damper pedal on a modern piano. – Modal Nest Jan 22 at 22:21

A combination of people.

First, unless you're playing from a facsimile of a period edition of the music, the person who prepared the modern edition of the music will have made some decisions in their translation of the notation to modern conventions, maybe filling in some missing information not customarily included at the time but helpful to modern performers, maybe making further additions aimed at helping people not trained in the style of the composer. And some editions are just plain wrong when looked at in the light of scholarship which has been conducted since their publication.

Second, if you're playing in a group then the group will make decisions. Maybe there's a person who does all that and just tells everyone else how to do it, maybe it's more of a group effort, but it will happen. Most older music is very sparse on things like performance directions, dynamics, ornamentation and decisions need to be made especially when playing with others as some choices individual players could make would conflict with each other despite both being valid.

Third, the actual performer, through their own training and abilities and also their choice of instrument upon which to perform the piece, as the instrument is highly unlikely to be the same as the kinds it was written for. Even HIP performers using "period" instruments aren't necessarily using exact duplicates or have their instruments configured in the same way. And again there's so much we don't know about authentic performance that we're making judgment calls all the time.

And of course all the influences on each performer from their teachers and colleagues and collaborators over their entire career.

So the answer to your question is "a lot of people". We may have studied early music, but we know we're making decisions about how to follow what we've learned. And more research is being done all the time, even as musical tastes change at the same time.


I had to carefully re-read your question to make sure you didn't really mean "who decides what is a historically informed performance?"

But the opposite of that - "who decides how to play for a modern performance?" - I think it is simply the editor of whatever modern edition being used.

For example, I have two editions of Bach's Two-Part Inventions, one by Mason the other by Palmer. They aren't exactly the same and there are differences that would clearly suggest different performances. Many of the editorial marking do not appear in autograph copies of the scores.

Tempo markings differ and Palmer gives metronome markings. Slurs are different. Expression marks like crescendo, forte, etc. differ and in some places the two editors contradict each other. Palmer gives about 15 pages of introductory text discussion issue about the inventions with historical context so I consider it more authoritative. Mason's was published in 1894 and Palmer's in 1991 so Palmer had the benefit of about 100 years of additional scholarship to rely on.


Historically informed is a very broad range of topics, depending on what the original period was. Note, that Beethovens era pianoforte was quite close to modern piano - at least if compared to a harpsichord. (Sometimes two manuals of the latter compensate for the loss of dynamic expression.) In Baroque harpsichord music, trills or other ornaments were required as substitute for any longer sounding tone, but they are seldom dropped for modern grand pianos, since the change may be more drastic than what the auditory expects.

In other instrument families the progress has less striking (e. g. gut strings and bows before Tourte) and the implications are far less clear.

As Michael points out, one decision is made by the editor of the chosen edition, but:

  • metronome markings, which are not authorized by the composer will typically be ignored (and are not much more than suggestions). Superfrequent dynamic indications strongly signal presence of such noise.
  • for professional soloists I can hardly imagine anything else but an urtext edition being used: while editor markings are eliminated by that, this is desired, since different decades had widely different ideas of useful editor additions. Less advanced artists may still use a carefully augmented edition, at least at the beginning for getting ideas. (This is similar to "training wheels" editions, where experts like well-known soloist added fingerings, bow marks, slurs or even whole cadenzas.)

This leaves the performer (in case of bigger ensembles the conductor, because all have to contribute to the same interpretation), who has to provide ideas of her own (education, training, practice), but this has to be done anyway, no matter how strict the score.


Who decides how such a historic piece is adjusted for modern instruments?

The performers.

Or do players learn to adjust themselves?

Of course. That's precisely what learning to play an instrument is all about, whether the piece was written in 1621, 2021, or any other year. No two performers play the same piece identically, and indeed the same performer doesn't necessarily play the same piece identically every time.

Part of learning to play the modern piano or violin or what have you is learning how to make music with the instrument rather than just playing the notes on the page. Phrasing, articulation, and expression are different on modern instruments as opposed to older ones, but if you consider a single instrument they also differ from one style of music to the next. Beethoven sounds different on a piano built in 1790, 1830, or today, but on a modern piano one plays Beethoven differently from Bach and differently from Brahms and differently from Stravinsky. Learning to play any instrument means learning to play all different parts of its standard repertoire effectively, and with the piano the standard repertoire reaches back to the 18th century, with occasional appearances by pieces from as early as the 16th.

On a larger scale (i.e. an Orchestra) and with enough ambiguity, it seems that decisions might be made which drastically change a piece. Or that modern assumptions about a composer/period would overly-inform how a piece is played.

Overly? What's "too much" here? Our modern assumptions are what they are. Perhaps they will change over time as we learn new things (or forget old things) about the past.

But our audiences are modern, too. All we can do is read what people wrote about performance practice at the time, see what we can learn from it, and produce the best performance we can. One person's idea of "best" will differ from another's. I saw a recording a few months ago of a master class given by the pianist Murray Perahia on a Bach piece. He mentioned that the music had been written for a different instrument and spoke of the things a pianist must do to deal with that. Different pianists approach the issue differently. But, as with all performances, the choices shaping the performance are the performer's.

In a comment, you ask:

It's interesting you put way more emphasis on players than other answers. I presume the average classical musician could play from any edition in your opinion?

I emphasize the performers (not always "players") because it is the performers who make the choices that the audience hears. One such choice is to decide which edition to use if multiple editions are available. That is, the editor's decisions are little more than advice to the performer. Even after choosing an edition, the performer can (should!) choose which of the editor's marks to observe and which to disregard. That is why a good edition makes it clear which aspects of the edition are in the source and which are due to the editor, as well as the reasons behind editor's choices.

It may not even be possible to notate subtle choices such as the one mentioned in the question, articulation of the third movement of the "Moonlight" Sonata. For example, there are infinite degrees of variability in the articulation of a simple scale. One infinitely variable parameter is the relative time between the damper of one note falling on the string and the hammer of the next note hitting its string (or perhaps these things happen in the opposite order). There is also the velocity of the hammer (and of the damper) to consider, and probably others besides.

These subtle distinctions can't be captured fully with articulation marks such as the staccato dot, a legato slur, and so on; there is only a finite set of permutations of this finite set of symbols. That infinite variability is the province of the performer alone; notation (and even instructions from a conductor, teacher, or coach) can only be a guideline.

  • Overly is maybe a bad word, as it is subjective I suppose. It's difficult on this particular SE to try to keep questions objective sometimes. I suppose I was thinking it would be something very noticeable to me which is a poor way to put it. I'm not sure how to quantify it so it's probably moot. It's interesting you put way more emphasis on players than other answers. I presume the average classical musician could play from any edition in your opinion? – Modal Nest Jan 22 at 14:36
  • 1
    @ModalNest I've edited the answer to address your question. I question "overly" because I inferred a question about whether a given performance might be sufficiently or insufficiently "authentic," though I don't suppose that's your primary concern. – phoog Jan 22 at 21:04

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