Arguably the most oft-sung tune in the world, “Happy Birthday to You” began as a simple song for school children. Penned in 1893 by sisters Mildred and Patty Hill, the song was originally called “Good Morning to All,” and was meant as a greeting from teacher to students. The original words were

Good morning to you
Good morning to you
Good morning dear children,
Good morning to all.

This simple little ditty was published in 1893 in the songbook, Song Stories for the Kindergarten. Over the years, the tune was modified several times. It first was revised to be a greeting from students to a teacher. Later, the words were changed again, and an individual child’s name was inserted into the third line.

At some point, the words were changed to reflect a birthday theme and “Happy Birthday to You” was born. No one knows for sure who made the change, or when it occurred, but it first appeared in print in 1924 in a songbook edited by Robert H. Coleman.

The new lyrics quickly gained popularity and the song’s fame spread through radio and sound movies. Western Union even used the song for its first singing telegram. Mildred and Patty Hill’s younger sister, Jessica, filed and won a lawsuit after the song was played without compensation in the Irving Berlin musical, As Thousands Cheer.

Chicago-based publisher Clayton F. Summy Co. published and copyrighted the tune in 1935. Today the music publisher Warner-Chappell holds the copyright to “Happy Birthday to You,” which brings in about $2 million annually. When is the song protected by copyright? Certainly whenever it is used for financial gain, as in movies or radio spots. But according to the ASCAP, royalties should be paid anytime it is sung in a public place, including restaurants.