The Academy Award-winning documentary Woodstock helped establish the events of that historic weekend in the collective mind of the public. But it didn't tell the entire story. Fifteen of the 32 artists who played the festival during the three-day concert are mostly erased from memory because they didn't show up in the 1970 film.

A large part of that is because the artists, or their handlers, wanted it that way. Some groups -- like Creedence Clearwater Revival, the Band and the Grateful Dead -- refused to allow their sets to be included in the movie, because they were unhappy with their performances, had contractual issues with the promoters or they just didn't expect the film to connect with a wide audience.

That all changed almost as soon as the movie and its soundtrack became smash hits. A second volume of music came out in 1971, and a home video, Woodstock: The Lost Performances, arrived in 1990. Milestone anniversaries in 1994, 2009 and 2014 led to more previously unreleased tracks becoming available on audio and video. The 2019 release of Woodstock 50: Back to the Garden – The Definitive 50th Anniversary Archive includes 38 CDs of music, omitting only three of the 435 songs that were played over the weekend, 267 of which had never been officially released. Some of the artists later released entire albums devoted to their sets.

You'll find 10 Artists You Didn't Know Played Woodstock below. We didn't include British psychedelic folk-rockers the Incredible String Band, Sweetwater (the first band to play Woodstock's stage), former Left Banke member Bert Sommer (who received the first standing ovation of the weekend, after he covered Simon & Garfunkel's "America"), Quill (the opening act on the second day) and the Keef Hartley Band (a British jazz-rock outfit whose namesake drummer had connections throughout the British blues scene).