Every so often, the music world is delighted by the discovery of musical works by long-dead classical greats, only to feel immense disappointment when some turn out to be fake.
The music world, just like other arts communities, is no stranger to deceptions.
Over the last 150 years, many musical forgers have published their music as Bach, Mozart, Haydn or lesser-known composers from history.
Plagiarism cases also showed musicians claiming other people's works as their own.
What motivated them to make these false claims?
Riding on famous composers' names
At the turn of the 20th century, French brothers Henri and Marius Casadesus regularly unearthed musical masterworks by Mozart, Handel, Carl Phillip Emanuel Bach and Johann Christoph Bach. The Casadesus brothers both performed and published those musical scores.
Musicologists eventually found out the brothers composed most of the music they claimed they unearthed. But by the time the ruse was uncovered, the music had been frequently recorded with the false attributions.
ABC Classic Mornings presenter Russell Torrance believes money was the motivation behind the Casadesus forgeries.
"People are more interested in music by Mozart than music by some random publisher-guy," he says.
Selling sheet music was quite lucrative in the past. But it wasn't until the 19th century when music publishing took off that composers became more assertive about the authorship of their music.
Torrance says the Casadesus brothers tried to meet the demand from people's curiosity and enthusiasm for music from the past. He admits he found their prank ingenious.
"To pass off their music as someone else's, they must've been very skilled composers," he says.
Money isn't the only reason people commit musical forgeries.
"There are women who've used the idea of a musical hoax to get around the fact that women aren't always taken seriously," says Alice Keath, presenter of What's On and Weekend Baroque at ABC Classic.
She highlights the case of 19th-century German composer Fanny Mendelssohn who published some of her music under her brother Felix's name.
After marrying a supportive husband and meeting fellow composer Clara Schumann, Fanny published music under her own name.
Stealing someone else's music
One of the more serious musical hoaxes happened in the 2000s.
British pianist Joyce Hatto is what researcher Lisa Giombini calls "a prodigy of old age".
With the help of her producer husband, William Barrington-Coupe, Hatto released no less than 1,103 CDs despite being seriously ill with cancer.
After Hatto's death, it was discovered that "She hadn't played one single note of all this impressive number of recordings," Dr Giombini says.
Many of Hatto's recordings were performances by lesser-known artists, re-released under her name after being digitally-treated by Barrington-Coupe. It was a classic case of plagiarism.
The deception came to light when Hatto's CDs were put through recording databases which identified the original performers.
Dr Giombini, who has researched many musical forgeries and plagiarism cases, explains why many people feel betrayed by Hatto's deception:
"Experts and amateurs were thrilled by the idea of this old lady playing the piano like a young virtuoso."
Even though the discovery was made a few years before his death in 2014, Barrington-Coupe was never prosecuted for his part in the musical theft.
Different attitudes towards authorship
Most musical hoaxes involve composers who are long dead.
Many of them were from the eras known as the baroque and classical music periods which span 1600-1800.
Most music scores from this time were scattered in private collections and archives which were not catalogued, making it easier for forgers to slip something in.
Keath cites Albinoni's Adagio, a piece of music which was supposed to exemplify a baroque composer's style but was instead written by his 20th-century biographer Remo Giazotto.
Another example is the much-recorded Ave Maria by 20th-century composer Vladimir Vavilov. After Vavilov's death, his music was misattributed to a 16th-century Italian composer Giulio Caccini.
It's believed one of the performers involved in recording Vavilov's music was behind this misattribution, assuming a long dead composer had more cachet than a recently dead one.
Keath says our attitude towards composers has changed over time, with people having a different idea of musical authorship in the past.
In the baroque era, "there were a lot of musical themes which composers passed around, so you don't really know who initially wrote it," Keath says.
Composers like Vivaldi, Bach and Handel borrowed tunes from their contemporaries as well as their own previously-written music.
This kind of borrowing was considered as a mark of respect and admiration.
Why we fall for hoaxes and deceptions
Nowadays, it's much harder to commit musical forgeries.
A recent discovery of a Chopin Waltz in the New York's Morgan Library and Museum archives underwent extensive tests to prove its authenticity.
But it doesn't mean we're immune from hoaxers and pranksters.
The arts world, for instance, was rocked by the revelation last year that some Picasso paintings at Tasmania's Museum of Old and New Art were fakes, painted by local artist Kirsha Kaechele.
In recent times large learning machine databases which power AI music generators have dwarfed the kind of plagiarism pulled off by Hatto and Barrington-Coupe.
What we know about the artists behind the music can influence how we appreciate their works, Dr Giombini says.
But Torrance doesn't think it means we should stop enjoying some of these hoax pieces, with one caveat:
"You've got to be honest and tell the audience the whole story."
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