A California judge has declared that there is enough evidence for Media lawyer Francis Alexander Malofiy’s lawsuit against Led Zeppelin to move forward, writes Victor Fiorillo of Philadelphia Magazine.

Malofiy went to federal court in 2014 to file a lawsuit against the group he claims stole parts of “Stairway to Heaven” from some long-gone group named Spirit.

The case was transferred out of Philadelphia’s court to the United States District Court in Los Angeles, and the judge there recently issued a ruling that has to have Robert Plant and Jimmy Page and company scratching their heads and feeling a little nervous. The trial is set to begin on May 10.

Malofiy filed the “Stairway to Heaven” lawsuit on behalf of Michael Skidmore, trustee for the Randy Craig Wolfe Trust. Randy Craig Wolfe, who died in 1997, was the frontman for Spirit, a 1960s band.

The suit centers on the introduction of “Stairway to Heaven” and accuses Led Zeppelin of, among other things, “falsification of rock and roll history.” Malofiy also wrote that Spirit “pioneered the psychedelic rock sound.”

The Spirit song in question is “Taurus,” an instrumental that clocks in at under three minutes. According to Wolfe’s estate, Led Zeppelin was undoubtedly aware of Spirit’s existence, claiming that the bands played at three of the same festivals. Malofiy submitted concert posters to back this up.

Court documents indicate that the surviving members of Led Zeppelin gave sealed depositions in which they said that they had no memory of this.

The experts for Wolfe’s estate submitted lengthy reports insisting that there are substantial similarities between the two songs.

It’s actually not the first time that Led Zeppelin has been accused of plagiarism and copyright infringement. As Malofiy dutifully documented in the lawsuit, there have been many similar claims involving “Dazed and Confused,” “Whole Lotta Love,” and “Communication Breakdown,” among other Led Zeppelin hits. Some of those claims reached settlements that included credit and royalties to the plaintiffs.

Click here to read more about the Led Zeppelin lawsuit.