 It is possible for a junior synonym to be given precedence over a senior synonym, primarily when the senior name has not been used since 1899, and the junior name is in common use.The older name may be declared to be a "nomen oblitum", and the junior name declared a "nomen protectum".This rule exists primarily to prevent the confusion that would result if a well-known name, with a large accompanying body of literature, were to be replaced by a completely unfamiliar name.