The use of shields of different colors and with various designs was central to the coat of arms and an entire body of literature came into being during the medieval period, detailing the significance of different types of shield designs.
The Coat of arms resolved this by allowing a person to be identified from a distance through the specific design of his coat of arms.
A wide range of symbols were used on heraldic shields during the medieval period. Like other aspects of the coat of arms, the specific symbols used on heraldic shields were used to denote certain meanings.
The use of zigzag lines on the shield, for instance, symbolised either fire and its properties or the sun and its majesty.
Similarly, the use of wavy lines denoted the sea, river or a waterbody depending upon the owner’s home. The use of a crenulated line denoted a specific town while uneven lines on heraldic shields represented land.
The specific colours used on heraldic shields symbolised different meanings. The use of the red colour, for instance, denoted that the owner of the coat of arms was a warrior or the owning family had a martyr. Blue colours represented loyalty and truthfulness.
Purple represented royal majesty and was typically limited to use in the royal heraldic shields. Black represented either the tenacity of the owner’s will or grief at some loss. White colour in heraldic shields symbolised peace and gold denoted the magnanimity of the owner.
Well-defined regulations in the medieval period specified what colours could be used by different sections of the society, such as knights and the actual nobility.
Apart from the choice of colours and symbols which gave meaning to a heraldic shield, the use of different kinds of stripes was also a common part of medieval heraldry. Different stripes denoted different meanings and they were frequently used on coat of arms.
Each type of stripe was also given a unique name of its own. A vertical stripe on the shield, for instance, was called a Pale and denoted military strength. A horizontal stripe was called a Fess and was used to represented honour.
A diagonal stripe, called a bend, was used to symbolise defence. A diagonal set of stripes, forming a cross on the shield, was used to denote the resolve of the owner. An angled stripe was called a chevron and denoted the faithfulness of the owner, usually to the Crown.
Shields were the defining pieces of armour of knights on medieval battlefields, long before other kinds of defence such as plate armour came into use.
It was for this reason that when the need for coats of arms arose, shields became the most popular and central elements used in the creation of heraldic achievements.