Knights were part of the nobility class.  Most knights were children of lords.  The knight was a professional fighter.  His duty was to protect the weak, the poor and the church.

As the children of lords, knights had a fairly comfortable childhood.  The children of lords, unlike peasant children, were not required to work until the age of seven or eight.  At that time, they were usually sent to the house of a friend or relative.  There, the boy would act as a servant to the lord and would receive his training as a fighter.  This was his period of education, and it was designed to teach him to be unquestioningly loyal to his lord, devoted to service to his lord, and to be courageous and fierce in battle, yet still be a gentleman.  This was the code of chivalry.  Knighthood was based on the ideas of chivalry, which included the belief that war is romantic and noble.  Values, such as loyalty, devotion, courage, and respect for the enemy were all part of chivalry.

When he reached the age of 18 or 19, a knight was sent out to travel with other young knights.  Because their main object was to fight, these bands of knights would rove around in search of a conflict.  When they found one, they would join the battle on whatever side seemed most appropriate to them.  When they weren't involved in local wars, knights traveled to tournaments in which they could test their fighting skills.  The tournaments lasted for days, if not weeks, and were marked by loud parties, gambling, drinking and prostitution.

As a fighter, the knight was equivalent to the tank of today.  His armour was almost impenetrable, such that relatively few knights actually died in combat, even if the fighting was brutal.  A small but very significant invention increased the fighting power of the knight considerably.  That invention, which came from China, was the stirrup.  The rider could brace himself by using the stirrups, and thus use his full strength as well as that of the horse for maximum advantage in battle.  The stirrup made jousting with long lances possible.  A good knight could gallop at full speed and use his lance to send other knights flying off their horses.

Although knights were to be the protectors of the poor, the weak and the church, they often terrorized as much as they protected. In the midst of drunkeness or battle, the code of chivalry was not always followed.

After traveling for two or three years, young knights returned home, still fully dependent on their father. Until his father died, a young knight could neither marry nor inherit property. This was a period of frustration for knights, because they could not get on with the business of marrying and setting up their own estate.