The traditional "Happy Birthday" song is considered the most popular song in the world according to the 1998 Guinness Book of World Records. However, it is a song with curious origins, with an owner and with copyright.
In 1893, American sisters Mildred and Patty Smith Hill, who were kindergarten school teachers in Louisville, Kentucky, wrote a book with songs for kindergarten children. The first song was called "Good Morning to All", a simple song to greet the children:
Good morning to you,
Good morning to you,
Good morning, dear children,
Good morning to all.
As a certain day it was one of the girls' birthday, Patty decided to keep the melody and change the lyrics of the song for "Happy Birthday to You", giving origin to the famous song.
In 1924, the song was published on a songbook by Robert Coleman, and then it became popular thanks to the radio and the cinema. It was then that the third of the Hill sisters, Jessica Hill, proved that the original song had been written by her sisters and in 1934 she obtained the copyright.
In 1935 the Summy Company, working with Jessica Hill, obtained a new copyright. In 1990 the Warner Corporation purchased that company for US$ 15 million and obtained the copyright, with an estimated value of US$ 5 million.
According to the laws, this copyright won't expire until 2030 in the United States (2016 in Europe), so any commercial use of the song should be authorized by paying the corresponding royalties.