Filmmakers, musicians, and anyone else wishing to perform “Happy Birthday To You” no longer has to worry about paying hefty royalties to Warner/Chappell, the publisher that has long claimed to hold the copyright for the ditty. Yesterday, a federal judge ruled that the classic party tune is in the public domain.

Earlier this year, some filmmakers behind Happy Birthday, a documentary about the song’s history, sued Warner to get back the $1,500 they were required to pay for its use in the film. During the process, they turned up what they believed to be the “proverbial smoking-gun” to prove that the publisher did not hold copyright for the song’s lyrics; at best, Warner could claim copyright over just a particular piano arrangement, the filmmakers claimed.

Around 1893, sisters Mildred and Patty Hill penned a song called “Good Morning To You,” which was subsequently printed in song books by publisher Clayton F. Summy, and is the basis for the birthday tune. The copyright on “Good Morning” expired in 1949, meaning the basic tune for the contended song is in the public domain.

The origin of the lyrics is less cut-and-dry. The earliest publication of the words for “Happy Birthday” were printed in a 1911 song book called The Elementary Worker and His Work. No author was credited, though the book mentioned that the song was to be sung to the tune of “Good Morning.”

After the song grew in popularity — appearing in multiple films and a stage play without permission from the supposed authors — Summy received copyright for the song in 1935. And thanks to the lobbying of Disney, copyright law has been revised (and will continue to be revised to protect Mickey Mouse) so that many things copyrighted after 1923 still haven’t entered the public domain.

But the U.S. District Court judge in this case ruled [PDF] there was no contractual agreement between the Hill sisters and Summy at the time. In fact, the Hills sued Summy in 1942, alleging that the publisher had allowed their music to be used in movies and plays without their permission. At the time, the Hills acknowledged there had been an agreement with Summy granting the publisher a “a number of licenses” for “various piano arrangements” for “Good Morning” and “Happy Birthday.”

That lawsuit was settled by the Hills reaching a new deal with Summy that transferred all of the sisters’ rights to the publisher.

Warner/Chappell purchased Summy in 1988 for $15 million and has been collecting royalties and going after alleged copyright infringers since.

However, in ruling for the filmmakers, the judge says that “Because Summy Co. never acquired the rights to the ‘Happy Birthday’ lyrics,” Warner/Chappell does not “own a valid copyright” on the birthday song.

The judge says the song’s authors never made any attempt to protect the lyrics of “Happy Birthday,” noting “They did not try to obtain federal copyright protection. They did not take legal action to prevent the use of the lyrics by others, even as Happy Birthday became very popular and commercially valuable.”

It wasn’t until 1934, when third sister Jessica Hill asserted the sisters’ rights to the melody, “but still made no claim to the lyrics,” according to the judge.

“The Hill sisters gave Summy Co. the rights to the melody, and the rights to piano arrangements based on the melody,” he writes, “but never any rights to the lyrics.”

This may not be the final word on the status of the classic song.

“We are looking at the court’s lengthy opinion and considering our options,” Warner/Chappell said in a statement.

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