When did the knights first appear?

The knights appeared long after the Roman Empire fell. Foreign raids usually happened a lot, such as the famous vikings from Normandy, hungarian magyars, and buvarian warriors. After a while people got frustrated and would turn to the local noblemen for protection. Nobles then started recruiting men who were wealthy enough to afford thier own equiptment. But in the beginning, most knights didn't look like that knight in shining armor that you expected. The armor was enfluenced years later by churches and women wanting to create well mannered men.