NEW YORK, NY.- On the surface, Ed Sheeran and Led Zeppelin might not seem to have a lot in common. Sheeran is a baby-faced singer-songwriter whose hummable ballads like “Perfect” and “Photograph” have become streaming-era pop standards. Led Zeppelin is a classic-rock colossus whose molten riffs are part of the foundation of heavy metal.

Yet when it comes to the recent history of copyright litigation in music, Sheeran and Led Zeppelin are practically joined at the hip. Both have been accused of copying other artists’ work in ways that are at the center of an evolving debate over just how much — or how little — of a piece of music can be protected by law.

Next month, Sheeran is scheduled to begin a long-delayed trial in federal court in New York over his song “Thinking Out Loud,” which the plaintiffs say copied elements of Marvin Gaye’s soul classic “Let’s Get It On.” (The litigation’s history is complex, involving three separate cases filed on behalf of owners of the rights of Ed Townsend, Gaye’s co-writer, who died in 2003.)

In some ways, “Thinking Out Loud” bears an obvious resemblance to “Let’s Get It On.” They share nearly identical chord progressions and similar bass lines. Aspects of the instrumental tracks on both recordings, like the tempo and drum sound, are close enough that when one YouTuber stitched the two songs together, it was hard to tell where one ended and the other began. (In this case, performance elements in the recordings are irrelevant; the suit involves only the underlying compositions.)

But are they close enough that Sheeran should be liable for copyright infringement? Or is their overlap limited to fundamental musical building blocks that are part of the public domain?

Courts have been hashing out these very questions in recent cases involving Robin Thicke, Katy Perry, the Weeknd and Dua Lipa — as well as Led Zeppelin, whose victory over an infringement claim against “Stairway to Heaven” could give Sheeran an edge. A detailed appeals court ruling in favor of “Stairway” addressed the knotty issue of what counts as infringement when two pieces of music are based on commonplace elements like scales, melodic fragments or simple chord progressions.

“All of these cases are about the question of how similar is too similar,” said Joseph P. Fishman, a professor at Vanderbilt Law School in Nashville, Tennessee. “The Copyright Act that Congress passed says nothing whatsoever about that question. In the U.S. copyright system, the rules for how that question gets answered are entirely developed by federal judges.”

Copyright suits are a standard hazard for successful pop musicians; they may be inevitable in an art form that relies so deeply on the influence of past works.

In fact, one go-to strategy for defendants is to point to “prior art” — examples from music history, the more distant the better, showing that a given melody or pattern has such deep roots that it may be public domain (or at least is not the exclusive property of a plaintiff). At trial, Led Zeppelin’s lawyers cited a 17th-century guitar sonata that, at one spot, sounds an awful lot like “Stairway to Heaven.”




The elephant in the room for all these cases is “Blurred Lines.” In 2015, a jury decided that the song by Thicke and Pharrell Williams infringed on the copyright of another Gaye classic, “Got to Give It Up,” and Gaye’s heirs were awarded more than $5 million in damages.

That result alarmed many in the music industry who thought the case involved basic genre elements that had long been considered fair game. In the wake of the verdict, lawyers reported an uptick in new claims.

The Led Zeppelin appeal, issued in 2020, sent the pendulum back in the other direction. The similarities between “Stairway to Heaven” and the song that challenged it, “Taurus” by Spirit — a band Led Zeppelin occasionally shared stages with in its early days — came down to an arpeggiated chord progression and a bass line that descended along a chromatic scale.

Elements like those, appeals court judges said, were so commonplace that they deserved only a so-called thin copyright. In that case, two works must be “virtually identical” for one to infringe the other, the judges said.

A week after that ruling was issued, it was cited by a judge who vacated a jury’s verdict that Perry’s hit “Dark Horse” had copied elements of a Christian rap song — a case that came down to a sequence of eight notes.

Peter J. Anderson, a lawyer who represented Led Zeppelin at the “Stairway” trial and appeal, called the appeals court’s decision an important clarification.

“These are basic concepts that you need to make music,” Anderson said. “You need to be able to put three or four notes together, and there are only seven notes in the scale.”

Even so, the results can be unpredictable because the facts of each case differ and a great deal of what a jury hears is decided by a judge.

Will the Led Zeppelin ruling help Sheeran? A handful of intellectual property lawyers polled for this article said the answer should be a resounding yes — though they hastened to add that jury trials could be unpredictable.

The judge in that case has already narrowed much of the evidence that can be presented to a jury. Gone is the bass, which does not appear in the sheet music “deposit copy” that established the copyright for “Let’s Get It On” in 1973. And in a pretrial ruling, the judge said the plaintiffs’ expert musicologist could not testify that the song’s chord progression or “harmonic rhythm” were unique or distinctive. There is uncontested proof, he determined, that those elements are common musical techniques.

This article originally appeared in The New York Times.