It seems only fitting that the most epic and dramatic of rock songs has resulted in one of the music industry’s most epic copyright fights.

“Stairway to Heaven,” Led Zeppelin’s 1971 megahit, defined rock radio for decades and helped make its credited writers, Jimmy Page and Robert Plant, extremely rich. For the last five years, it has been caught up in a copyright infringement case that has gripped the music industry. In a hearing scheduled for Monday, a panel of 11 federal appellate judges in San Francisco will delve into the song’s authorship.

At issue is who wrote the song’s famous acoustic opening passage — Mr. Page and Mr. Plant, or Randy Wolfe of the 1960s psychedelic band Spirit. A larger question that could be settled by the court concerns what, exactly, constitutes an original song.

Image Mr. Page and Mr. Plant in 2012. They won a trial in the case, which was filed by a trustee for a song, “Taurus,” that appeared on Spirit’s debut album in 1968. Credit... Evan Agostini/Invision, via Associated Press

With the music industry shaken by copyright decisions in recent years — like the $2.8 million award that the creators of Katy Perry’s hit “Dark Horse” were ordered last month to pay to a Christian rapper — the Led Zeppelin case has become a cause célèbre for songwriters, intellectual-property lawyers and even the Trump administration, which took the unusual step of filing a brief in support of Led Zeppelin.