The one thing that the horse and the knight needed was armor. The horses armor was very protective. Its armor was shaped like the horses neck and up. On the back was a steel plate shaped like its back. The cloths on the inside of the armor are called mail.
Mail are little rings that are attached to each other.
One hard blow of the sword would maybe cause a broken bone. What really helped the knights were steel plates. They would use steel plates for the whole body. A hard blow would cause a bruise. This was the best armor.