 "Kuhschelle" points to a 1410 mention in a Frankfurt archive; the OED lists 1440 as the earliest attestation of a "bell-wether", the leading sheep of a flock, on whose neck a bell is hung.The OED also attributes the phrase "to bear the bell" in the sense "to take the first place" as originally referring to the leading cow or sheep of a drove or flock to Chaucer's "Troilus and Criseyde", 1374.In 15th-century Germany, a cow bell was worn only by the best and leading piece of livestock.