This is a big birthday month for our family. Between us my husband and I have five brothers and sisters whose birthdays fall within the month of March, which means that if we were better siblings than we are, we’d spend a lot of time singing “Happy Birthday to You,” loudly and really off key, into the phone.

We don’t have a perfect record, but when we do manage to get the crew together to sing, it’s quite the ridiculous auditory experience for the recipient who greatly appreciates the effort, I’m sure.

It’s strange, really, that we sing so poorly given what a simple little tune the traditional birthday song is. Originally it was designed to be sung by kindergarteners, and at first it had nothing to do with birthdays at all.

It was in the early 1890s when Kentucky school teacher Patty Hill introduced the “Good Morning to All” song to her kindergarten class. Arranged by her sister Mildred Hill, the song first appeared in a collection called Song Stories for the Kindergarten published by Clayton F. Summy in Chicago. It was just a little diddy that was easy for the small kiddos to learn and helped remind them to focus at the beginning of each school day. And it was a simple enough tune that it could be easily adapted for other uses, like wishing a happy birthday, whenever the need arose.

We used such songs with my children when they were young. When as toddlers they were learning to brush their own teeth, we sang what I cleverly named “The Toothbrush Song,” which featured brilliant mommy-on-the-spot lyrics such as “I’m brushin, brushin brushin, brushin, brushin my teeth so I don’t have stinky bad breath.” It helped to liven up the experience and reminded them of how long to keep brushing.

That’s exactly the kind of thing “Happy Birthday to You” was, a song for teaching a life skill, before it became one of the most legally contentious tunes in history.

The song caught on, and showed up in numerous compilations throughout the early decades of the twentieth century, for the first time with the birthday lyrics in 1912. It appeared in the 1931 Broadway musical The Band Wagon and in Irving Berlin’s 1933 As Thousands Cheer. It became the song to sing at family birthday celebrations. It’s identified in the Guinness Book of World Records as the most recognized song in the English language and has been translated into at least eighteen additional languages. “The Toothbrush Song” has yet to catch on quite so well.

Patty Hill and The Summy Company filed a series of lawsuits over the use of the song and in 1935 registered the copyright that would frustrate an awful lot of people for the next eighty years, including birthday celebrators in restaurants forced to wear silly hats in the middle of a circle of clapping waitstaff singing some song that sounded even more made up on the spot.

The Summy Company changed hands a few times and eventually became part of the Warner Bros. entertainment conglomerate, a company that for quite a while was making an easy $2 million per year on licensing that one silly little kindergarten song. It was serious business. Even Star Trek got in trouble for singing the song translated into Klingon.

Any use of “Happy Birthday to You” outside of intimate family gatherings or obnoxious phone renditions performed for unfortunate siblings required a license that would cost from seven hundred to ten thousand dollars, making it possibly the highest-earning song in history.

Then in 1998, the US Supreme Court heard a case involving the Copyright Extension Act, which gets occasionally updated primarily in order to protect Mickey Mouse from ever entering the public domain. The Court upheld the copyright in that case, but in the dissention, the traditional happy birthday song got a mention.

That led law professor Robert Brauneis to do a little research into the history of the song and eventually determine that the copyright could only apply to the specific arrangement initially published by The Summy Company a very long time ago, and that the claim Warner Bros. held on royalties for any performance of the song was pretty shaky. That conclusion led to further lawsuits and a hefty settlement for Warner Bros.

So if, instead of sticking to a truly terrible phone rendition, you want to sing “Happy Birthday to You” to your sister while she wears a ginormous sombrero at the local Mexican restaurant, or if you want to use it in your Broadway musical, or perform it on the jumbotron at Lambeau Field, go right ahead. As of June 28, 2016, the song is in the public domain in the United States. In Europe, too, since January 1, 2017. And if you’d like permission to use “The Toothbrush Song,” just let me know. I’m sure we can work something out.