After less than a day of deliberation, a California jury has found the members of the legendary group Led Zeppelin (and their record label) did not copy the famous opening riff of Stairway to Heaven from an earlier song by the band Spirit. Applying basic copyright principles, the jury found that while Jimmy Page and Robert Plant may have heard Spirit’s song Taurus before composing the opening of Stairway, the songs were not “substantially similar.”

The verdict contrasts with another recent high-profile copyright infringement case in which a California jury found that Pharrell Williams, Robin Thicke and Clifford Harris infringed Marvin Gaye’s classic Got to Give it Up when writing Blurred Lines. The Blurred Lines jury rejected similar defense arguments that the songs were not “substantially similar.” (A previous blog on the Blurred Lines verdict can be found here.)

The two cases illustrate the fact-sensitive and often unpredictable nature of the “substantial similarity” test. What remains certain, however, is that successful artists will continue to be challenged on the provenance of their works, even long after those works first topped the charts.