Heraldry developed in the High Middle Ages based on earlier traditions of visual identification by means of seals, field signs, emblems used on coins, etc.
[1] The origin of the term heraldry itself (Middle English heraldy, Old French hiraudie) can be placed in the context of the early forms of the knightly tournaments in the 12th century.
The kite shields shown in the Bayeux Tapestry (c. 1070) sometimes show simple cross or spiral ornaments, but no heraldic emblems.
Similarly, Frankish or German round shields of the 11th century (Ottonian, Salian) are sometimes depicted with simple geometric ornamentation, but not with figurative emblems.
[2] Early mention of heraldic shields in Middle High German literature likewise dates to the 12th century.