[ Dramatic music plays ] -Salzburg, Austria.

Home to one of the greatest composers the world has ever known... ♪♪ ...Wolfgang Amadeus Mozart.

Born more than 250 years ago, his music continues to inspire musicians, composers, and audiences around the world.

But could there be more to the story of his compositions?

-Just look at the name, "Wolfgango Amadeo Mozart."

That date has been etched on by somebody else.

♪♪ -Wolfgang Amadeus Mozart died tragically young at 36 years of age.

♪♪ A prolific composer of more than 600 works, he left behind many unfinished compositions and only a partial catalog of his official works, which has left the door open to centuries of dispute and revision about which are true Mozart compositions.

Now, musicians, artists, and researchers around the world have become captivated by another question.

-There is Wolfgang at the harpsichord.

Next to him is a woman with her hands on the keys, intertwined, playing together.

Who was she and why do we not talk about her?

♪♪ -Wolfgang's older sister, Maria Anna, was the first prodigy in the family.

She rivaled his talents as a virtuoso performer.

And there's evidence that she also composed.

Could Maria Anna have collaborated on Mozart's early works?

And can her own compositions be found?

-What we would have to find is her music calligraphy on a first draft.

-Using the tools of modern forensics, researchers are attempting to unravel a 250-year-old mystery.

♪♪ ♪♪ [ Bells tolling ] ♪♪ [ Indistinct conversations ] ♪♪ Every year, millions of people make the pilgrimage to Salzburg, to walk in the footsteps of Wolfgang Amadeus Mozart.

♪♪ Treasured objects from his life can be found here -- the instruments he played and the places where he lived.

The International Mozarteum Foundation houses the world's largest collection of Mozart family artifacts.

And hidden inside his family home is a precious store of original documents and music scores.

♪♪ ♪♪ ♪♪ One of the items in the collection includes the earliest evidence of Wolfgang Mozart's incredible gift and his musical partnership with his older sister, Maria Anna, known as "Nannerl."

♪♪ -Leopold Mozart was the most important teacher of his children.

He certainly taught them music.

-Dr. Eva Neumayr is a senior researcher and archivist with the International Mozarteum Foundation.

Her special interest is investigating the role of the women in the Mozart family.

Eva wants to use surviving documents to bring these women out of the shadows.

-In 1759, Leopold gave a music notebook to his daughter.

The notebook was very precious for her, and she kept it until the end of her life.

♪♪ -Maria Anna was eight years old when she began her musical education.

It would not be long before her brother, Wolfgang, five years younger, joined her at the keyboard.

-Wolfgang went to the piano and tried to find notes and he was a very fast learner.

♪♪ ♪♪ -Maria Anna's notebook documents the earliest stages of the Mozart children's musical education.

Its pages provide precious insight into how Leopold taught his children both to play and to compose music.

♪♪ -Here we have a page where the Mozart siblings both wrote on.

The first lines are by Wolfgang, and the other lines are by Maria Anna.

Those exercises were exercises in harmony and counterpoint, and Leopold Mozart must be credited with also educating his daughter in this way.

-The notebook is now in fragments, scattered all over the world in different collections.

It's not known exactly how many pages it originally held.

What makes it so special is that it contains the first musical works by Wolfgang Mozart, composed at the astonishing age of five years old.

♪♪ -He started writing music very early, much before he could write music.

So Leopold had to write the pieces his son composed down for him.

Later on, Wolfgang got his own music book, of course, but the Nannerl notebook is very famous because it has his first compositions.

-Maria Anna was also learning to compose music.

But there are no known compositions by Maria Anna in the book.

Has her work been lost?

-With Mozart, what was intriguing was at five years old, we were supposed to believe -- or four or five years old -- that he was capable of composing complex music.

Maria Anna was five years older and obviously exceptionally gifted.

But as a young female at this time, no value will have been placed on what she wrote.

The problem is that nobody wanted to look for Maria Anna.

They were not interested in finding her, so they didn't look for her.

-Retired professor and orchestra founder Martin Jarvis is on a quest.

He believes that Maria Anna has been overlooked in the Mozart story and is hunting for evidence of her musical achievements.

And the first place to look is what's left of the childhood notebook.

-The notebook contains the handwriting of Amadeus, it contains the handwriting of their father, Leopold, and then three people who they refer to as Anonymous One, Two, and Three.

My examination of this book has been quite substantial, right?

And it seems to me that there's far more of Maria Anna Mozart in here than people give credit to.

I started examining the name on the front cover of Maria Anna's notebook.

I noticed this very strange form of uppercase "M," and because I could map this against Maria Anna's handwriting in letters, I could conclude that this must be Maria Anna.

And then I looked at the minuets and the marches and spotted the same.

This "M" here is very similar to one of the "M"s on the front cover, just like this.

So, we've got -- the "M"s are all consistent with the front cover.

Is it possible then that some of those minuets and marches are actually compositions of Maria Anna?

So, I presented this idea to my colleague in the USA, Heidi Harralson.

She came at it from a different angle.

-There is uncertainty around the authorship of many pieces in Maria Anna's notebook.

But could the latest advances in forensic handwriting analysis help uncover more information?

♪♪ -I'm a forensic document examiner.

That could be like anonymous notes, death threat letters, bank robbery notes, I've worked on those, divorce cases, people writing in blood on the side of a wall in a crime scene.

If it involves handwriting, I've worked on it.

I'm investigative.

That's like one of the top words I would use about myself, and I feel like I'm always seeking for the truth.

I like kind of digging into questions or materials or looking for the truth in, like, handwriting or documents or in art or in manuscripts.

I'm not afraid to be challenged or to debate about what the truth is either.

-Heidi Harralson also works to authenticate high-value artworks for collectors.

With her work, she has seen art from many of the great European masters, as well as a number of forgeries.

So, this is an exhibit of a questioned Claude Monet signature from a painting, that's being questioned as to whether the painting is actually a Monet or not.

Usually, forgeries will look like they're stopping and starting.

They look like they're drawn and slowly moving.

Each stroke at the end, it looks like it's stopping, and then there's a little pool of paint at the ends of the strokes.

But it's the "M." The "M" in Monet is what really gives the signature away.

-Heidi has clearly established that the top Monet signature is a forgery.

-This is somebody who doesn't have the motor memory associated with this signature to make it look fluent.

And motor memory is very, very important.

When we're writing our signatures hundreds, thousands of times, we develop a habit with it where it's -- and it's called motor memory.

It's so automatic that we could even sign it blind.

-A signature is like a fingerprint, unique to each person.

What traces of her handwriting did Maria Anna leave behind?

-We compared the writing on the front of the notebook with the signature of Maria Anna found on letters that she wrote.

Specifically, what we found was the classical way that she writes the "M," with the baseline.

She has this ink-filled little loop.

And then, as she continues to write, she's writing this kind of calligraphic, fanciful version of the "M." And then also we see her classic "Z," which is a sort of a manuscript "Z" with a cross in it.

-Heidi now turns her attention to the opening pages of music in the notebook.

-When I compare what's in Maria Anna's notebook, yeah, I definitely see a correspondence.

The handwriting, almost like a print script, does resemble Maria Anna's handwriting.

She's a careful writer.

I've already seen that in her normal writing.

So, I would not expect her to be sloppy in her music calligraphy.

In fact, I would expect her to have the kind of precision that I'm actually seeing in this writing, because it corresponds with actually how she writes.

There's really nothing to say that she didn't do that right here.

I think it would be a little bit surprising if we did not find her writing in this book.

Everyone else's writing is in this book.

-The notebook was the beginning of an extraordinary musical journey for the two children.

Their father, Leopold, a court musician and composer, knew their talent was a chance to secure the whole family's future if it was managed well.

And there was only a short window of time to exploit this opportunity.

-I mean, this was a dreamer.

His passion was music.

And to have these children be so brilliant -- "miracles from God," he called them.

And he felt it was his duty to show the world God can do this, this is what he wrote.

-Sylvia Milo has spent years researching the Mozart family and inhabiting the character of Maria Anna for her theater production, "The Other Mozart."

-Two years after the very first piano lesson that Nannerl had, the father arranged a tour for both of the children as child prodigies.

-The children traveled with their mother and father on a daring adventure.

-They had a huge, three-and-a-half-year journey.

♪♪ They left when Mozart was eight, and got back when he was 11.

♪♪ -Imagine being a young child, first of all, to go from Salzburg to Vienna, quite a distance in that time.

To be in a coach, what about food, where do they stop?

And then they made their way all the way to Northern Europe, to the Netherlands, and then from the Netherlands to the court in Paris, and then from the court in Paris over to London.

That was huge in the 18th century.

-The two children stunned the world with their talent, playing in the highest courts and palaces.

In their early years of touring, Maria Anna got top billing, above her brother.

-She was obviously very gifted.

In fact, her father writes that she is one of the finest keyboard players in Europe.

-"What it all amounts to is this, that..." -They had all sorts of successes and all sorts of times of thin pickings.

Leopold was prepared to make the children play anywhere, whether in the royal palace or indeed in a pub.

They would play in taverns.

-The children became seasoned performers.

They played the most difficult music of the time, usually only played by adults, and would even improvise on the spot for delighted audiences.

♪♪ Taking a closer look at this period of the children's lives also provides new evidence to support the investigation into Maria Anna's composing.

♪♪ ♪♪ A key event happened in 1764, when the Mozarts traveled to England.

In the first summer of the tour, Leopold became very ill, and the family retreated to the countryside near London.

What happened next puts Maria Anna at the center of the music making.

-Leopold got sick, so the children are told to keep quiet in the house.

And I'm not sure if we know who came up with the idea to write a symphony.

♪♪ -This symphony in E-flat major, "K-16," is known as the first Mozart symphony.

Dame Jane Glover is one of the world's preeminent conductors of Mozart's music.

-It's an astonishing piece of music, and it never ceases to amaze me that this is the product of an eight-year-old child.

-So, these two little ones were left to their own devices to write music.

I'm very curious, and we can only speculate, as to whether Nannerl and her brother, Wolfgang, wrote it together.

-She was the one who wrote it all down for him and orchestrated it.

We know this from Nannerl.

Nannerl, in later years, told this to one of Wolfgang's biographers.

I mean, orchestrating could be a real, huge undertaking.

So, perhaps Wolfgang wrote the melody, and she orchestrated the whole thing.

I think it's safe to say it was a collaboration.

-He says at one point, "Remind me to give something really good to the horns."

So, she's part of this.

Even composition is, at this point, just another game.

Not allowed to play, so we'll write music instead.

♪♪ ♪♪ ♪♪ ♪♪ ♪♪ -Just as handwriting has distinct patterns, each composer uses certain patterns and rhythms that are unique to the individual, sometimes referred to as their "voice."

It is another method by which authorship of musical compositions can be identified.

♪♪ -How can I tell a piece of Mozart from a piece of Haydn?

They're writing at the same time, effectively.

Why can I tell the difference?

We can probably put it down to the way in which a given composer utilizes the palette of colors that are available in harmony.

And it is simply to do with the way in which a composer manipulates the sound, right?

That's really it.

-If a composer's voice is recognizable in their works, what can be found in Mozart's "Symphony No.

1 in E-flat major, K-16?"

♪♪ -There's a lot of different characters that are inside this symphony and I've often thought, is there a character of the young boy or is there a character of the elder sister?

And I think I've got a feeling that the wisdom of an eldest child really comes forward in this symphony.

-Paul Dyer is the Artistic Director of the Australian Brandenburg Orchestra, a world leader in historically informed performance.

-Let's see if we can do the last two notes even quieter.

-He brings decades of experience to his analysis of the "voice" of the first symphony.

[ Orchestra playing ] ♪♪ -It's in three sections.

There's a fast opening, and then that comes to a close, and then there's a slow section.

I can feel that there's a lot of depth coming from her in this work, particularly the sincerity of the second movement, of the slow movement.

It opens with a very warm couple of phrases, but then it goes very solemn into these exquisite slow chords and it makes me think that it was her speaking.

♪♪ ♪♪ ♪♪ ♪♪ And then there's a third section, which is the finale.

The final exuberance of Wolfgang comes in the first and third movement.

♪♪ -Back in the Salzburg archives, there are some tantalizing clues left by Maria Anna about how the two siblings worked together on Mozart's earliest symphonies.

-So in this letter, she relates the story of her writing down his first symphony.

She says that they were in London and Leopold was very sick and they were not allowed to touch a piano.

So Wolfgang started composing and told her how to write it.

-We have to take into consideration that Nannerl, as a respectable woman of the times, was incredibly humble.

She probably didn't mention fully the story of this composition and perhaps others.

♪♪ -Nearby, in Vienna, young composer and child prodigy Alma Deutscher has remarkably similar experiences to the Mozart children.

-People used to call me when I was younger a little Mozart or would compare me to Mozart and I -- actually, I always hated that.

♪♪ I never wanted to be a little, sweet child prodigy.

I always wanted to be taken seriously.

I wanted to be accepted for what my music is and not just for how old I was when I wrote it.

-Okay.

-The bassoon has to play loudly, louder, because otherwise you can't hear it.

-The... -Yes, yes, yes, yes.

-And also the clarinet.

-Yes, the clarinet played a little bit louder.

-Yeah, yeah.

-[ Speaks German ] ♪♪ ♪♪ -When I grew up, Mozart was really my mother tongue in music.

I loved Mozart's melodies and his style, his harmonies, his modulations, his wit, his sense of humor.

Also, the simplicity, very often.

I loved his sister as well, Nannerl Mozart.

She was one of the most inspiring figures for me when I was a child.

-As a composer, Alma's experiences can give us rare insight into the mind of Maria Anna Mozart... -I think that there's no way that she was just writing down mutely what he was telling her.

I'm sure that she would have argued, or she would have said, oh, why don't we try this?

Or she might have given him an idea, or they might have discussed something and, and both had their own opinion.

♪♪ -Just as the Mozart children did during performances, Alma also improvises live on stage.

It is a form of composing, even though it is not usually recorded.

♪♪ Improvising is probably the most important way for me to get inspiration.

I'm sure that Mozart would have improvised, and Nannerl would have improvised a lot, and that's how a lot of their music would have come to them.

I mean, they would improvise together when they were children all over Europe, and she had a good understanding of harmony and of counterpoint.

♪♪ I often thought about how much she could have helped him or how close they would have been also musically.

The celli crescendo to...

The sad thing is that we don't know how much we've lost with all these very talented composers and musicians who were never taken seriously.

♪♪ ♪♪ -When the Mozart family finally arrived home from their grand tour more than three years later, Maria Anna was 15 and Wolfgang was 11 years old.

♪♪ It was the end of Maria Anna's performing life as a paid musician.

-Leopold Mozart stopped taking her and showing her off in other countries as a piano player once she was a grown woman because that didn't have the right taste to it.

♪♪ -She was considered an adult at 15, and things were no longer the same for her.

She really had to behave as a lady.

It was also the family's reputation, rested on her behavior.

In some of these countries it was equal to prostitution, if you were performing or displaying yourself in such a manner.

-They were performing something for money, and that was something that was not well respected in the 18th century for a woman.

♪♪ -Wolfgang's musical education became the sole focus.

-There are reasons why Leopold, it seems, didn't push for her to become a composer.

And those reasons are because she couldn't get a position as a court composer, as a woman.

She couldn't earn money as a composer.

So, the emphasis was for Wolfgang to be spotlighted as much as possible with this gift he had.

If she had the same gift, it still wouldn't have been emphasized because there was no future in it for her.

-Women were so constrained in the 18th century, it's hard for us to comprehend.

-Music historian Sarah Fritz is a passionate advocate for women who created music, despite the restrictions they faced in Maria Anna's time.

-Women were expected to be mothers and wives.

Their lives were about serving the men around them, and they were the property of those men.

They were really having to fight for just the fact that they had souls that were human and had value.

-This was the Age of Enlightenment, and you would think that these men had progressive views on on the situation of women, but they didn't.

-The Enlightenment was a philosophy that spread across Europe that was defined by the age of reason, scientific thought, civic freedom.

It did not flow through to women.

It also did not flow through to people of other races.

It was very specific to the rights of men.

-The world of classical music is almost entirely a record of men's musicianship and composition.

-You're talking about a world which is struggling even now to recognize this, the creative skills of females.

-The most recent research by the DONNE Foundation shows that less than 10% of music played by the world's top orchestras is by female composers... And most concert programming is consistently dominated by the same 10 male European composers.

♪♪ In Maria Anna's time, women were actively discouraged from writing music, and the work of those who did was not valued, preserved, or played publicly.

But through the extraordinary efforts of archivists and researchers, work by women from that era is being uncovered today.

-I found out how many female composers had been around in the 17th, in the 18th century, in the 19th century, and I got really mad that I had heard nothing during my university time of those female composers.

So I decided -- with a few colleagues, decided to do something against that.

♪♪ -Eva is bringing the work of female composers to light, after hundreds of years in the shadows.

She holds concerts of music by forgotten female composers, performed in Salzburg, in spaces similar to where Maria Anna performed.

♪♪ There is evidence in the Mozart family archives that Maria Anna did not give up on her musical life, despite becoming a wife and mother.

♪♪ -We know that Nannerl composed.

We do have letters that refer to her compositions.

♪♪ -The story of her missing compositions reveals much about the times.

♪♪ After Maria Anna was retired from performing publicly, Wolfgang and Leopold left for Italy.

It was their first tour without her.

♪♪ Leopold and Wolfgang were on a quest to secure a job in a large court, and Italy was the heart of the music world in 18th-century Europe and the birthplace of opera.

-Wolfgang and Maria Anna write to each other regularly.

They are very close siblings.

Wolfgang is essentially a boy still, and he of course misses his mother and sister.

-Both Leopold and Wolfgang try to let them take part in their travels... ♪♪ -But there is one problem -- Maria Anna Mozart kept the letters of her father and her brother, but her father and her brother did not keep her letters.

They just didn't think them important and just discarded them.

Or maybe she didn't think them so important, and that's also possible.

We don't know what happened to these letters.

♪♪ -Of the more than 700 handwritten Mozart family letters that have been preserved, just fragments of a handful of her letters remain.

-Letter writing was expensive, so they used as little paper as possible.

Some of Maria Anna's letters survived because she wrote on the bottom of a letter Wolfgang began, or vice versa.

♪♪ -The letters also reveal that Maria Anna was writing her own music during this time.

♪♪ -One time they speak of a song, and one time the letters speak of a minuet where she did the bass line and did it very well.

-There's a particular letter where Wolfgang praises her composition, and begs her to compose more.

-Maria Anna sent her composition to her brother in Rome.

But there's no record of where the document may have gone next.

Her composition could be sitting unknown in a private collection or archive.

-It's really heartbreaking we don't have the composition.

We don't know what happened to it.

Perhaps it is somewhere, but it seems unlikely that this would be the only thing she would have composed.

It was probably the best thing she thought at the moment to show to him.

I'm sure she composed many things before she sent that one.

♪♪ -Music written by women was regularly discarded at the time, and surviving works were often overlooked.

It has made finding their scores particularly difficult.

♪♪ -Interest in women's documents started in Europe I would say around 2000 or so, or maybe 1980s at the earliest.

I have seen that, as an archivist, that an older archivist say, "Oh it's, uh, female work, just throw it away."

So that happened a lot.

And even women discarded works of women's because they were part of the whole system and didn't think women's work valuable.

So that's why in female biographies we have a lot of blank spaces.

-With so many records lost or destroyed, and others lying uncatalogued in private collections, restoring the place of women in music history is an enormous challenge.

-An archive search is what's required to see if we can find those documents.

But the problem is getting access to those archives is not easy.

It's distinctly possible that materials that might have represented her work were just pushed aside because she was not interested in pushing it herself, but her brother, right?

And trying to get recognition for him.

So, it's possible that somewhere in Salzburg, in a loft somewhere, that there's a pile of manuscripts entirely by Maria Anna Mozart.

-In recent years, there have been explosive discoveries, which have rewritten musical history... including the work of another sister who lived in the shadow of her famous sibling.

-Fanny Hensel came from a very musical family whose name you might have heard of.

She was born a Mendelssohn, and her younger brother's name was Felix, who is the one you've probably heard of.

Fanny Hensel was a composer who taught her younger brother.

She was extremely prolific, over 400 works.

But she didn't publish very much music and her first compositions that were published were actually published under her brother's name in the early 1830s.

She wrote to her brother that she had to shove her compositions down the publisher's throat to convince him to publish them, even under her brother's name.

Felix and Fanny's handwriting was very distinctive.

So scholars can tell the difference, and there's been some discrepancy of people finding works that were written by Fanny, but being in denial that a woman could write a work like that -- her "Easter Sonata" being the primary example.

The person who owned the manuscript for quite some time refused to let scholars look at it because he didn't want to find out that it was actually written by Felix's sister.

Fanny left a diary entry that mentions the "Easter Sonata."

We know she wrote one.

She left behind a notebook that had pages missing from it.

The scholar found the "Easter Sonata," with the page numbers that matched the book, not to mention her handwriting that looks like Fanny's.

More recently, scholars have been starting to publish her unpublished works.

It's very exciting.

-Discoveries like these are incredibly rare and can take years of intense sleuthing, sometimes in the face of fierce resistance.

♪♪ -There does seem to be a cognitive bias problem in the art world.

There is a belief system around it.

It's kind of hard to bring in forensic evidence and kind of shift the bias, especially if that belief system has been going on for hundreds of years or if the piece is very valuable, because nobody wants their pieces devalued.

♪♪ -With her childhood notebook as their starting point, Martin and Heidi discuss their theories.

Martin's initial hypothesis was that the opening pages could have been written and composed by Maria Anna.

♪♪ But the Mozarteum Foundation has a different view.

In the 18th century, the music that Maria Anna and Wolfgang learned was hand-copied.

Eva Neumayr and her colleagues' analysis of the handwriting in the notebook points to another person's involvement.

-Leopold Mozart paid a professional copyist of the Salzburg Court to write most of the pieces into the book.

We can see that several of these pieces also appear in other keyboard books from Salzburg at the time.

This was a repertory of music which was used for the education of young musicians.

-Copying music notation was a laborious process, and some of it was done by professional copyists.

One of Salzburg's best-known copyists was a colleague and friend of Leopold Mozart.

So, this is one part of the "Mass K-220" by Wolfgang Amadei Mozart, and it is written, copied by Josef Richard Estlinger.

He's one of the three main copyists of the Mozart time.

This is a very typical example of his writing.

He has very round heads of the notes.

That's Esslinger's copying style and very typical.

His copyist's hand could not be confused with the hand of Maria Anna Mozart because he has totally different clefs.

No, he couldn't be confused.

-For Eva, there's no question that the handwriting in the first pages of the notebook belongs to the Salzburg copyist Esslinger, putting an end to the theory that those pages could be by Maria Anna.

-We have an example of her handwriting as a child.

Well, we have several, actually, but this is one of them.

And here, the longer she writes, the clearer her handwriting evolves, and it already has some of the elements which we see in the music writing she does much later.

So it couldn't be her handwriting.

So, it's absolutely impossible.

And we know his handwriting very, very well.

-When Heidi is given access to Salzburg copyist Esslinger's scores for the first time, she reconsiders Martin's theory that Maria Anna's handwriting is on the early pieces.

-Yeah, I definitely see a correspondence in that this piece could be copied.

It could be a copyist.

That is certainly possible.

-Heidi's revised opinion brings mixed emotions to Martin Jarvis.

-It's a very frustrating and deflating feeling to feel like you've gone down a rabbit warren and just hit the end and discovered nothing.

-But while these pages have now been positively identified as copied by Esslinger, there are still many others which are unaccounted for.

♪♪ If other pages of the notebook could be recovered, they might contain compositions by Maria Anna.

The problem in Maria Anna's case is that so few documents have been preserved.

And there's an added complication -- even Mozart's own documents are confusing to track.

♪♪ In the last seven years of his life, Wolfgang began to organize his compositions into a thematic catalog, clearly identifying his most significant works.

Martin has now turned his attention to discrepancies in the catalog as another potential way to find Maria Anna's compositions.

-The five violin concertos are fascinating.

Each of the manuscripts has had the date changed.

That date has been etched on by somebody else.

So there was something very odd.

Just look at the name -- "Wolfgango Amadeo Mozart."

I noticed that there were these pieces by Amadeo Wolfgango Mozart and Wolfgang Amadeus Mozart.

So, I started deconstructing that.

Mozart had a thing about his name, so sometimes he would write his name backwards -- "Trazom" -- right, right?

Sometimes he would sign himself "Amadeo" and "Wolfgango Mozart," right?

So -- but in none of the letters did he call himself "Amadeo Wolfgango Mozart."

So, to me, this meant that this is a different person.

-Heidi compares a verified signature of Wolfgang's from his wedding certificate with the inscription that Martin has found on the autographed score of a violin concerto.

-There was this unusual name variation that seemed like kind of uncommon, even for him, and the handwriting didn't look the same either.

The "M" is executed with this flaring stroke at the beginning, but then when we look at Mozart's signature from the marriage certificate, it's written much more quickly and more angular.

It's highly likely that the person writing "Amadeo Wolfgango Mozart" on some of these documents is not Wolfgang Mozart himself.

And in comparing that writing with Maria Anna, Maria Anna's writing is much closer, comparatively, than Mozart's writing is.

I'm not really hypothesizing who wrote the violin concertos, but it does not appear that Mozart wrote the names on the concertos.

♪♪ -The work cataloguing Mozart's music has gone on for centuries, by the family, by music publishers, and historians.

In his short life, Mozart wrote more than 600 pieces of music.

Many manuscripts were retrospectively annotated to date and label them as Mozart's works.

-After Mozart was dead, for a century or more, people were claiming that they had Mozart works, and people were composing in the style of Mozart and selling them the manuscripts.

So, publishers were very happy to publish music without any proof that it was by Mozart.

Because if it's -- if they said it was by Mozart, well, that was fine.

♪♪ -Mozart's music, his autographs are all over the world.

There's a lot in Berlin.

There is a lot in Poland, in Krakow.

There's some in Vienna.

But there's also a lot in the U.S.

So, if you want to see the autographs, you have to travel.

-Adding to the problem -- the documents themselves are continuously on the move, as they're bequeathed or sold between institutions and private individuals.

-500,000 is bid, 500 in the room... -Original Mozart documents are worth hundreds of thousands of dollars.

-800,000 on the left.

-The stakes are high for anyone who attempts to challenge the historical record.

-Composers during this period often didn't identify their signature at the end of their work or at the opening of their work, unlike artworks.

♪♪ There have been so many revisions to the Mozart catalog.

It's been going on for hundreds of years.

Mozart died at 36, so there was a lot of pieces that didn't make it to the catalog.

There were a lot of unfinished pieces of music that he wrote.

At least 60 works that have been attributed to Mozart have been removed from the catalog.

♪♪ Here I've got a symphony, "Symphony No.2, K-17" from the Kirschl catalog, that was once attributed to Mozart, but recent discoveries have just shown that it's in fact by Mozart's father, Leopold Mozart.

♪♪ Here's Mozart's "Sonata in C, K-19d."

Originally attributed to Mozart, but it's off the catalog.

There's a lot of dispute as to whether it's authentic Mozart.

♪♪ -It's been the life work of many musicologists to untangle the true authorship of Mozart's works, a painstaking pursuit that continues to this day.

-You know, some of these documents are from the 1700s, so they're hundreds of years old and there is an assumption around them.

And I think that makes this case that much more difficult, because we're dealing with lots of contaminated evidence, too.

♪♪ I probably have less of an agenda than Martin does, okay?

I mean, yeah, it's nice to find that Maria Anna may be -- you know, may be a composer like Mozart was.

But I don't have a vested interest in that.

I feel like this is a bit of a messy case.

Seems like there's some common sense that she did some composing, but we're having a hard time finding the smoking gun.

-One challenge Heidi faces with this case is that she is only able to look at photo reproductions of the notebook pages.

-I much prefer to have the original and, of course, with the original then I can do analyses on the paper.

And then, of course, looking at the graphic details I can see a lot more just in the ink image.

♪♪ To definitively state that Maria Anna is a composer, I think what we would have to find is her music calligraphy on a first draft, and it's not a copied piece.

Until we find that with Maria Anna, I don't think we can definitively state that she is a composer.

-While her compositions still remain undiscovered, what is clear is that Maria Anna's virtuosic playing and creative partnership with her brother continued throughout their lives.

-Everybody praised her technique.

Wolfgang certainly admired her fantastic skill and wrote for it.

You know that this is their sibling relationship, writ large.

-After her brother's death, Maria Anna continued to champion Wolfgang's compositions, playing them on his concert piano.

♪♪ In her later life, Maria Anna began performing publicly again, and was lauded as one of Salzburg's finest pianists.

-She never stopped piano playing, and that's what made it possible for her to make this comeback.

♪♪ -She always thought of herself, definitely, as a virtuoso pianist.

♪♪ I just love this idea that she didn't give up.

♪♪ -I suppose that what keeps me going, even though it's difficult, is knowing that I'm not alone.

That there are other people who suspect things.

If it turned out that Maria Anna Mozart was the genius composer, she's still a Mozart.

♪♪ -In archives around the world, there are still thousands of documents and scores that sit uncatalogued.

Their mysteries wait to be revealed.

-Occasionally, something new comes out, and of course, there are also lots of pieces lost, so we hope to find them someday.

♪♪ -Somewhere in the world are her compositions.

♪♪ If we finally had a concert of music by Maria Anna Mozart, that would make me feel very happy.

♪♪