For He's a Jolly Good Fellow
"For He's a Jolly Good Fellow" is a popular song that is sung to congratulate a person on a significant event, such as a promotion, a birthday, a wedding (or playing a major part in a wedding), a wedding anniversary, the birth of a child, or the winning of a championship sporting event. The melody originates from the French song "Marlbrough s'en va-t-en guerre" ("Marlborough Has Left for the War"). The traditional children's song "The Bear Went Over the Mountain" is sung to the same tune.
According to the Guinness World Records, "For He's a Jolly Good Fellow" is the second-most popular song in the English language, following "Happy Birthday to You" and followed by "Auld Lang Syne".