There is no evidence that coats of arms were passed down from generation to generation until the Middle Ages. The hereditary element of heraldry did not become common until armor came into popular usage and heraldic symbols were recognized as leader's emblems. When this idea spread and became adopted in the wider populace heralds became a necessity. The job of the herald was to ensure that the rules of heraldry were followed and there was proper differentiation between coats of arms in order to protect against infringement of copyright of a particular coat of arms. They also would ensure that no two men would bear identical coat of arms. Heralds were very similar to modern day ambassadors, they did not engage in combat and were accorded many privileges and were held in very high regard.
Heralds originally worked as free-lancers, organizing and keeping score at jousting tournaments. When helmet's became popular with knights for safety reasons they began to place identifying marks on their clothing and shields. Heralds became experts at recognizing the knights by their coat of arms. The next logical step was for these heralds to begin recording the coat of arms of knights. They developed rolls which were painted versions of each coat of arms. Since heralds were the experts in this area knights wishing to assume new coats of arms would consult with the herald prior to assuming new arms. The herald would inform the knight if the arms he wanted to assume conflicted with any existing coat of arms.