The writer of the song "Happy Birthday to You" is unknown. While some attribute the song to sisters Patty and Mildred Hill, the origin of the song is widely disputed.
Some historical reference attribute the melody of the song "Good Morning to You" to Patty Hill, but others believe the Hills sisters merely borrowed the melody and set their own lyrics to it. Additionally, the Hills sisters never claimed "Happy Birthday to You" as their own during their lifetimes. Warner/Chappell Music has long claimed to have a copyright to the song and has made lots of money licensing the song to various customers; however, its rights to the song have been highly disputed, and most believe the song rightfully belongs in the public domain.