Well, that would be the famous song "The Twelve Days of Christmas," written in 1780 by an unknown author. It's a traditional Christmas carol that's been sung and celebrated around the world for centuries. It's a joyful and whimsical song that tells the story of a mysterious "true love" who sends the singer a series of gifts over the course of twelve days. The song is full of festive imagery and humor, and it's been adapted and interpreted in many different ways over the years.