Heraldry was developed during the Middle Ages because of the difficulty to recognize sides and individuals in military situations. By wearing heraldic symbols (some examples include birds, lions, certain colored stripes, etc.) men could identify opposing soldiers or even individual knights. Symbols of heraldry would often appear on surcoats, shields, and banners. As it developed, heraldry became a symbol of stature and of social class. Rules even developed about how familial coats of arms would change and become integrated together through marriage.