"Sumer Is Icumen In"—an English ballad actually sung in the 12th century—is featured throughout the series. At times it is heard as background music at parties. In "The Betrothal", Sir Richard's son plays it on his flute while his betrothed sings it. In the episode "Carlotta", Little John sings it to his sweetheart. In "The Path of True Love", Marian sings it to stall Sir Charles. In one of its most prominent uses, Robin forces a group of soldiers to sing it. It's worth noting that this melody was whistled by Little John before his first meeting with Robin in the Hollywood feature film "The Adventures of Robin Hood" (1938).