Image copyright Reuters Image caption Led Zeppelin guitarist Page (right) and lead singer Plant say they wrote Stairway to Heaven in a remote cottage in Wales

Members of the rock band Led Zeppelin have appeared in court to deny borrowing from another song for their 1971 classic Stairway To Heaven.

Guitarist Jimmy Page and singer Robert Plant are expected to give evidence at the civil case in Los Angeles.

They are accused of lifting the song's opening notes from Taurus, a 1967 track by the band Spirit.

Page, 72, and Plant, 67, are being sued by a trust acting for a founding member of Spirit who died in 1997.

The case began with the jury being played various performances of both songs, including part of Led Zeppelin's recording of Stairway to Heaven.

In his opening statement, the plaintiff's lawyer, Francis Malofiy, said the case could be summed up in six words, "give credit where credit is due".

Page and Plant were both "incredible performers, incredible musicians but they covered other people's music and tried to make it their own," he alleged.

The band's lawyer Robert Anderson insisted that the two men "created Stairway to Heaven independently without resort to Taurus or without copying anything in Taurus".

There was no proof that they had even heard Taurus until decades after creating Stairway to Heaven, said Mr Anderson.

Mr Anderson also claimed that the part of the song at issue - a sequence of notes in the opening bars - was a "descending chromatic line…something that appears in all kinds of songs".

Such a "commonplace" musical device which "goes back centuries," was, he claimed, not protected by copyright which in any case, he argued, was not actually owned by the plaintiff.

At the scene: James Cook, BBC News

Smartly dressed in sober suits and ties, two of rock's biggest stars arrived early in Courtroom 850 to defend themselves against accusations of plagiarism.

As the room filled with the familiar strains of Stairway to Heaven, Jimmy Page leaned back and closed his eyes, his head nodding gently as he listened to his own performance and to the vocals of his bandmate Robert Plant, seated beside him at the front of the court.

With their hair pulled back in ponytails the two men looked relaxed and attentive, at one point pulling on their spectacles as they leaned towards each other to discuss a concert bill which had been produced in evidence.

The Beatles, Elvis Presley and The Sound of Music were all invoked in the opening statements of a trial which is scheduled to last four or five days.

Just before it began, a member of the plaintiff's legal team hovered at the back, behind the ranks of reporters, clutching a guitar in a case. "It's a prop," he explained.

In the corridor, long-haired fans of Led Zeppelin lined up to be sure of a seat.

One of them, Byron Taylor, 57, a retired teacher from San Bernardino, California, proudly clutched a signed copy of Stairway to Heaven. He was here, he said, to witness "a bit of history".

At an earlier hearing, US district judge Gary Klausner had ruled that the two pieces of music were similar enough to let a jury decide whether Page and Plant had infringed copyright.

Taurus, a two minute and 37 second instrumental with a distinct plucked guitar line, was released by Spirit in January 1968.

The copyright infringement action is being taken by a trust set up to manage the legacy of the late guitarist Randy Wolfe, also known as Randy California, a founding member of Spirit who played on the same bill as Led Zeppelin later that year.

He died in 1997 while saving his son from drowning.

Lawyers for Wolfe say Page and Plant wrote Stairway To Heaven after hearing their client play Taurus, and that he should be given a writing credit.

Page and Plant say the song was their masterpiece, written in a remote cottage in Wales.

The plaintiff is reportedly seeking royalties and other compensation of around $40m (£28m).

According to Bloomberg Businessweek, Stairway To Heaven had earned $562m (£334m) as of 2008.