Knight's armor went through many changes. In the 12th century, the knights used an armor called mail. Mail was very little chains linked together to make one big suit of armor.
These suits took on average about five years to make. These suits also took a lot of money to make.
Those suits lasted until the 15th century and then they started to make full body suites out of plate armor. Helmets varied some covered the face and some did not. Some had decorations on them such as eagles beaks. Horses had to wear armor too.
A knight had to follow special laws and this was called chivalry. These laws were difficult to follow because there was a lot of them. they had to be well behaved near women. A knight had to keep his word no matter what the case. the case.