Wagner was an enthusiast, but it apparently sent Brahms to sleep.
These days, Liszt's Piano Sonata in B minor is regarded as one of the pinnacles of the piano repertoire, difficult for listeners and monumentally challenging for the pianist.
There has been 150 years of disagreement about its structure and its form - is it in one section? Three sections? Four sections? What's it about? Some suggest it's based on the Faust legend.
Others say it represents the story of the Garden of Eden.
Or perhaps it's biographical.
It's one of the most discussed and analyzed pieces of music ever written.
This week on Discovering Music, Stephen Johnson gets to grips with Liszt's masterpiece, before a live performance by Nelson Goerner at Wigmore Hall.
Stephen Johnson investigates the mysteries of Liszt's Piano Sonata in B minor.