Generations of aspiring guitarists have tried to copy the riff from Led Zeppelin's "Stairway to Heaven."
Starting on Tuesday, a Los Angeles court will try to decide whether the members of Led Zeppelin themselves ripped off the riff.
The band's guitarist Jimmy Page and singer Robert Plant are named as defendants in the lawsuit brought by the trustee of guitarist Randy Wolfe from the band Spirit. Attorneys for the trustee contend that 1971's "Stairway to Heaven" copies music from the Spirit song "Taurus," which Wolfe wrote in either 1966 or 1967. Wolfe died in 1997, drowning while saving his son in Hawaii.
Page, Plant and their bandmate John Paul Jones are all expected to testify at the trial, though Jones has been dismissed as a defendant in the case.
Led Zeppelin and Spirit performed at some concerts and festivals around the same time, but not on the same stage.
U.S District Judge R. Gary Klausner ruled in April that evidence presented in hearings made a credible case that Led Zeppelin may have heard "Taurus" performed before their song was created.
Francis Alexander Malofiy, attorney for Wolfe's trustee Michael Skidmore, said while many copyright cases are an uphill battle, Klausner's ruling brings his client one step closer to getting Wolfe credit for helping create one of the most recognizable song introductions in rock history.
Led Zeppelin's attorneys argued that both "Stairway to Heaven" and "Taurus" use notes and combinations that have been circulating in music for centuries.
The song has generated hundreds of millions of dollars over the years. Wolfe's attorneys overcame statute-of-limitations hurdles to sue over "Stairway to Heaven" because the song was remastered and re-released in 2014.
The lawsuit also came after a high-profile victory last year when a federal jury found that Robin Thicke and Pharrell Williams had copied a Marvin Gaye song to create their 2013 hit, "Blurred Lines" and awarded Gaye's children $7.4 million.
A judge trimmed the award, and the verdict is under appeal, but the decision appears to have prompted a surge in copyright-infringement filings.
The same attorney who represented Gaye's family filed another suit last week in Los Angeles saying Ed Sheeran's 2014 song "Photograph" is too similar to the 2009 song "Amazing" written by Martin Harrington and Thomas Leonard.