An attorney who has represented the Beatles and Michael Jackson has referenced The Beatles' While My Guitar Gently Weeps in the opening day of the copyright infringement trial over Led Zeppelin's Stairway to Heaven.

Led Zeppelin singer Robert Plant and guitarist Jimmy Page are accused of stealing the opening chords of their 1971 classic from another band. The pair appeared in a Los Angeles court for a civil trial on Tuesday, reports Reuters.

Larry Iser, a lawyer not directly involved in the case, said in a phone interview that the opening riff in dispute, which features a minor key and a descending bass line, is a common musical device.
Iser said that it has been used on the Beatles' While My Guitar Gently Weeps and Led Zeppelin's own recording Babe I'm Gonna Leave You.

Plant (67) and Page (72) did not speak to each other or their lawyers when they appeared at a federal court in LA. Both sported long grey hair and Page wore a three-piece suit.

Robert Plant 

The lawsuit alleges that the opening chords of their song was stolen from the 1967 instrumental Taurus by the band Spirit. 

US District Judge Gary Klausner said in April that a jury might find "substantial" similarity between the first two minutes of Stairway and Taurus, and to let a jury decide whether Plant and Page were liable for copyright infringement.

The lawsuit was brought by Michael Skidmore, a trustee for the late Randy Wolfe, also known as Randy California, Spirit's guitarist and the composer of Taurus.

Jimmy Page

Skidmore said Page may have been inspired to write Stairway for Led Zeppelin after hearing Spirit perform Taurus while the bands toured together in 1968 and 1969, but that Wolfe never received credit.
Stairway to Heaven is considered one of the most widely heard compositions in rock history and is Led Zeppelin's signature song.
Lawyers for Led Zeppelin have argued the chord progressions cited in the civil lawsuit, were so cliched that they did not deserve copyright protection.