Led Zeppelin's plagiarism trial over the authorship of "Stairway to Heaven" moved into its sixth day, and singer Robert Plant took the stand to stretch his memory on whether or not he saw the band Spirit perform at a club back in the day.

Plant and Zeppelin guitarist Jimmy Page are on trial for allegedly stealing the guitar intro to the band's classic 1971 song "Stairway to Heaven." The estate of Spirit's late guitarist, Randy California, claims that Plant and Page stole the music from California's 1968 song "Taurus," which was included on his band's debut LP.

According to The Hollywood Reporter, Plant confirmed that he visited Birmingham's Mother's club "40 to 50 times" in the late '60s and early '70s, calling it a "clubhouse for local musicians to hang out." But he noted that he would be in the bar, "because it would've been rude to talk where the performers could see you," and said the he couldn't remember seeing Spirit perform.

Spirit's bass player, Mark Andes (who later joined Heart), said he met Plant at the show and played snooker with him. But the singer said, "I don't have a recollection of mostly anybody I've hung out with." He also added that he doesn't know how to read or write music, a point made by Zeppelin's attorney to show that Plant couldn't have told Page how to play the opening notes of "Taurus" had he heard the song performed at the club the night in question.

Plant also said that "Stairway to Heaven" was written at Headley Grange, the recording and rehearsal studio often used by the group. “I sat with Jimmy by the fire and he began playing," he said. "I had a little couplet that fitted into what he was playing.”

So far in the trial, which started last week, Page revealed just how huge his record collection is, a music expert testified that the descending guitar lines in "Stairway" and "Taurus" are 300 years old and Zeppelin bassist and keyboardist John Paul Jones, who's not named in the case, made an appearance.

Led Zeppelin Albums Ranked Worst to Best

More From Ultimate Classic Rock