Medieval times includes about 1000 years. To put that into perspective, the end of the middle ages is considerably closer to today than to the beginning. A lot changed over that time, and knights weren't even a thing for the first couple hundred years or so.

There was also HUGE amounts of variation geographically, the Italians would look very different from the French at certain times, and in others they would look quite similar, but look different from the Germans.

If you want a specific time and place I can probably help, or I can give some generic examples for an assortment of times and places.