the merchant taylors and the skinners have always disputed their precedence, so once a year (at easter) they exchange sixth and seventh place. this is one of the theories for the origin of the phrase "at sixes and sevens", as the master of the merchant taylors has said a number of times, although the first use of the phrase may have been before the taylors and the skinners decided to alternate their position. both companies had been founded before the birth of chaucer, who was one of the first people to use the phrase, so it may have dated from before him.