A knight in chain mail
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Within a civilization, the comforts of life are based entirely around the level of technology that the civilization has created. For instance, the civilization that discovered how to create fire would be considerably warmer than those who did not, and those who have mastered iron are much more dangerous to go up against in battle than those who rely on bronze! Within the middle ages, weapons forged of steel and iron were to be watched out for, and what better repels an iron sword than another iron sword? Here, suits of armor were developed and used to their fullest.
A knight in plate mail
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Before "plate mail" (see the figure to the right) was developed, people used chain mail (see the figure on the left). Chain mail is created by linking chains of thin wire metal in hoops, creating a "net" of metal that was worn over their shirts. Even though this form of protection could not fully protect against a stab wound, these shirts of metal rings were very effective at deflecting arrows (Slater, 18).

Over time, knights wore less chain mail and more iron/steel plate. Plate mail, as it is called, is armor that is made out of sheets of metal. Plate mail is more effective than chain mail at blocking thrusts, stabs, and arrows. However, plate mail was heavier than chain mail, but not heavy enough to stop a knight from mountain his horse without assistance (Slater, 20).

With the choices in armor, there was still one problem remaining. How could you tell who was who under several layers of iron? It was impossible to change the armor a different color (as steel cannot be dyed like cloth), nor could you paint it. The solution? Make the parts and pieces you can, colorful. These were the surcoats (the sleeveless, long shirts that are worn over the plate mail), and the shields. It was mostly the shields that were painted, as surcoats were quick to get dirty with both dirt and blood, not to mention become ripped on the battle field.

So, how  does heraldry tie into this?