Explain why knights had coats of arms on their armor?

To clearly display their identity

In the Middle Ages, clearly recognizing a knight on the battlefield was a very practical necessity. The armor covering the entire body and the closed helmets made it impossible to identify the person underneath. As a result, knights displayed a coat of arms— a sort of personalized symbolic design, painted on a shield or directly on the armor. Thanks to the bright colors and unique patterns of these heraldic emblems, everyone could instantly recognize who was who. Each symbol or color often had a specific meaning, reflecting the family or particular history of the knight in question.

To illustrate their rank and reputation

Knights displayed coats of arms on their armor to highlight their social status and military accomplishments. The more a knight gained fame, the more his coat of arms became known and respected. Certain specific symbols on the shields or armor clearly indicated their rank in the noble hierarchy or their connections to a powerful family. It was somewhat their business card, visible to all. A practical and effective way to constantly remind everyone that they were not just anyone on the battlefield and in medieval society.

To allow for quick recognition in combat.

Knights wore coats of arms to be quickly recognized on the battlefield. It wasn't easy to identify oneself under heavy armor or a closed helmet. These colorful and clear symbols allowed immediate identification of allies, even in the heat of battle or amidst general chaos. No more hesitation before striking: one could tell at a glance who they were dealing with (enemy or friend). Quick, efficient, and above all, it avoided silly or tragic mistakes!

To intimidate opponents on the battlefield.

Coats of arms also aimed to create a strong visual impression, meant to impress or even terrify the enemies facing them. Some knights used aggressive symbols, such as beasts, menacing dragons, or prominently displayed weapons. Bright and contrasting colors like blood red, dark black, or shining gold reinforced this intimidating effect. Essentially, the idea was simple: to clearly announce to the opponent that the bearer of this coat of arms was not there to mess around.

To strengthen the sense of belonging and loyalty.

Wearing a coat of arms was somewhat like wearing the jersey of your favorite team today: it clearly displayed which clan, family, or lord you belonged to. The coat of arms helped the knight feel connected to his brothers-in-arms, his region, or his king. By displaying the same colors and symbols, it created a strong team spirit and a sense of loyalty towards his lord or family. It also showed your commitment and loyalty, qualities highly respected in medieval times. It was an effective way to remind everyone (and himself!) that the knight was not fighting just for himself, but for something greater: a cause, a family, a territory.