I remember hearing Julie Andrews sing this on one of those old Firestone Christmas song collections and I’ve liked it ever since.
“Patapan” (or “Pat-a-pan”) is a French Christmas carol in Burgundian dialect, later adapted into English. It was written by Bernard de La Monnoye (1641–1728) and first published in Noël bourguignons in 1720. Its original title is “Guillô, Pran Ton Tamborin”.
The carol revolves around the birth of Jesus Christ, and is told from the perspective of shepherds playing simple instruments—flutes and drums—the onomatopoetic sound of which gives the song its name; “patapan” is meant to mimic the sound of the drum, and an accompanying lyric, “tu-re-lu-re-lu,” the flute.