Lawyers representing Jimmy Page and Robert Plant asked a judge Monday to end the ongoing Led Zeppelin copyright infringement trial. According to the Hollywood Reporter, the songwriters allege that the plaintiff has not fulfilled the requirements for a burden of proof that “Stairway to Heaven” stole its opening progression from the Spirit song “Taurus.”

Ownership of “Taurus,” written in 1967 by the late Randy “California” Wolfe, is the biggest point of contention from the Zeppelin camp. Their lead attorney, Peter J. Anderson, has brought into question whether Wolfe’s trust has the right to sue, thanks to representative Michael Skidmore’s testimony.

According to Anderson, Skidmore’s explanation meant that Wolfe "assigned his renewal rights to Hollenbeck [Music, Spirit’s publisher]," therefore designating Hollenbeck the owners of “Taurus.” or to put it in legalese: "Further, since Skidmore abandoned his prior beneficial ownership claim, he has no basis to sue and judgment is proper in defendants’ favor.”

While U.S. District Judge R. Gary Klausner has yet to rule on team Zep’s requests, it was he who deemed the suit fit to go to trial in April 2016. Klausner determined that Skidmore and his lawyer, Francis Malofiy, had cause to claim “Stairway” plagiarized “Taurus.”

“While it is true that a descending chromatic four-chord progression is a common convention that abounds in the music industry, the similarities here transcend this core structure,” Klausner wrote in his 20-page opinion. The papers also noted that the descending bass on both songs is almost identical.

Page, Plant and their publishing company, Warner, have denied the charges, suggesting the progression has been around for 300 years and that the statue of limitations has long passed. Page and former Led Zeppelin bassist John Paul Jones have taken the stand for the defense, in a courtroom spectacle that has seen Page playing air guitar and Malofiy questioning the influence of a Mary Poppins song on “Stairway to Heaven.”

Robert Plant's 10 Most Historic Concerts