Although the use of various devices to signify individuals and groups goes back to antiquity, both the form and use of such devices varied widely, and the concept of regular, hereditary designs, constituting the distinguishing feature of heraldry, did not develop until the High Middle Ages. It is very often claimed that the use of helmets with face guards during this period made it difficult to recognize one's commanders in the field when large armies gathered together for extended periods, necessitating the development of heraldry as a symbolic language, but there is very little actual support for this view.