“Happy Birthday to You,” a song intertwined with copyright controversies, gained prominence in the public domain after a successful lawsuit. The melody, originally created by the Hill sisters, was subsequently copyrighted and licensed for commercial use. However, the copyright’s validity was challenged and ultimately invalidated, allowing the song to be freely used and adapted. The song’s popularity was cemented through its association with country music, becoming a ubiquitous part of American culture and demonstrating the evolving nature of music copyright law and the concept of fair use.