It is one of the most recognisable openings to any song in rock and pop history, but is it original?
That is the heated argument currently under way in a Los Angeles courtroom over "Stairway to Heaven", the best-known track from rock giants Led Zeppelin, pictured in their heyday. The band's guitarist Jimmy Page and singer Robert Plant are accused of copying the 1971 song's iconic opening from "Taurus", an instrumental recorded three years earlier by a much lesser-known band, Spirit.
Despite some fairly obvious similarities between the two tracks, both Page and Plant deny the accusation, saying they created Stairway to Heaven independently.
You might ask why it has taken the best part of 50 years for the case to get to court, and the main reason is that the wheels of justice grind very slowly. In fact the copyright infringement action is being brought by a trust set up to manage the legacy of Spirit guitarist Randy California, who died in 1997.
Much of the courtroom argument will centre on how much Page and Plant were influenced by hearing the earlier Taurus track, if indeed they had ever heard it before writing Stairway to Heaven. Lawyers for Taurus claim they must have, as both bands were active at the same time and even played at the same events. Even if they didn't deliberately copy the track, they would have been influenced by it claim the plaintiff's lawyers, who are seeking royalties and other compensation amounting to around £28M.
Conversely, the legal team for Page and Plant insist there is no proof they even heard Taurus until decades after writing Stairway to Heaven, which they did in a remote cottage in Wales without copying anything at all. They say the contested sequence of notes in the opening bars is a "descending chromatic line" – a commonplace musical device which goes back centuries and appears in all kinds of songs.
Apart from the passage of time making it difficult to prove who might have heard, what, where and when, the real question at the core of the case is how can you prove that if two things are similar, one must be copied from the other? With only 12 notes in the chromatic scale which underpins all western music, and billions of songs written using that scale, isn't it inevitable that some sequences of notes will be used time and time again?
How often have you heard people say "Modern pop songs all sound the same to me" or "That song playing on the radio reminds me of..."? It must be impossible to write anything recognisable as western music which has not already been written before in a very similar, if not identical, way.
The outcome of the case in America could be pivotal in determining whether countless other 'alleged copyright infringement' cases go ahead. Unusually, it is up to a jury to decide if Led Zeppelin copied from Taurus (perhaps without even knowing it!), or if they just happened to use a similar arrangement of notes in their most famous track.
To hear snippets from both songs click here and make up your own mind.