Heroic figures, they are the symbol of ultimate trust to the people of any kingdom.
If the king wars with the knight's lord, the knight's honor demands that he choose the side of right. The knight must go to his lord and formally remove himself from the lord's service. Once that is accomplished, he may then offer his services to the crown.
Knights are bound by the laws of chivalry at all times. These include valor, nobility, fairness, courtesy, respect for women, protection of the poor, and many others.
A boy who wished to become a knight would leave home at about the age of seven to begin his training. At this time, he would join the household of some great Lord as a page. While a page, he learns the behavior expected of a knight, and trains with smaller versions of the weapons he will use when he is older.
At 15 or 16 years of age, the boy becomes a Squire, or personal servant of the Knight who is his master.
The Squire waited on the Knight at his table, and rode with him into battle. After about 5 years, the squire is elligible for Knighthood.