The Adelaide Concerto

As someone who lives in a place called Adelaide, and knowing that our town was not on Mozart's gig schedule, the Adelaide of the concerto's title was Princess Marie Adélaïde de France, one of the many (legitimate) daughters of Louis XV.  The "lost" manuscript of c.1766 was "found" in 1933.

Mozart's Adelaide Concerto might arguably be his greatest achievement, mainly because it is now known that he had been dead for quite some time before the piece was composed.

Only an extraordinary composer with Mozart's talent might have achieved such a feat, though I am rather skeptical about anyone having the ability to work at a musical composition while buried in a mass grave.

It is reasonable to agree that Marius Casadesus did not uncover a long lost manuscript by a 10-year-old Mozart.  The hoax fooled some very well known musicians, as far as I am aware.  A man named Einstein (the musicologist not the physicist) managed to figure it out, though.