At the beginning of the Middle Ages, the knight was little more than a mounted soldier who served a lord. Over time during the feudal period, the church began “laying the grounds for a medieval code of chivalry … by forbidding knights from attacking women, priests, peasants and merchants”1 This ‘chivalry’ is probably what you are thinking of as the ‘spirit of knights’. The word chivalry itself comes from the French word chevalier, which means someone who rides a horse. Chevalier also became the French word for knight.

There was never a fixed code followed by every knight, so the meaning of chivalry varied somewhat from place to place and over time. But virtues often raised up by chivalry included:

mercy, courage, valor, fairness, protection of the weak and the poor, …being faithful to God, protecting the innocent, being faithful to the church, being the champion of good against evil, being generous and obeying … (and) a general gentleness and graciousness to all women.4

Being that knights were human, they often did not live up to the lofty ideals and the high standards set for their behaviour. But in much of the West it is the ideals and the chivalry that is remembered when thinking of knights and not the bloody behaviours that would have been part of their lives as soldiers.

Source:

1. “Medieval Code Of Chivalry Provided A Guide In Uncertain Times”, (http://www.medieval-castle-siege-weapons.com/medieval-code-of-chivalry.html) 18-Oct-2009
   
   
2. “Medieval Time Knight – the Evolution of Nobility”, (http://www.medieval-castle-siege-weapons.com/medieval-times-knight.html) 18-Oct-2009
   
   
3. Snell, Melissa. “Defining the Knight”, (http://historymedren.about.com/cs/knightsarmor/a/kl1define.htm) 18-Oct-2009
   
   
4. Wikipedia. “Chivalry”, (http://en.wikipedia.org/wiki/Chivalry) 18-Oct-2009