Training for knighthood during medieval times usually began at an early age. Often the prospective knight was sent to live with a relative or lord who had the resources to train the young boy in use of weapons and, most importantly, the skills to handle a horse in combat. A knight-in-training would often serve as a squire (assistant) for an established knight, attending his needs, helping him don his armor, and making ready his horse and weapons.
Once his training was completed and he reached “fighting age” (usually around 16-20 years old), he would ceremoniously become a full-fledged knight. The ceremony became more elaborate as the Middle Ages progressed, until only the richest nobles or a king could afford to “knight” someone.
The new knight now served his liege lord (which may or may not be the king himself), bound to offer military service up to 40 days a year in peace time, more, as needed, in war time. Military duties included castle guard, serving in the lord’s “bodyguard”, and participating in battle.
Apart from military duties the knight could also participate in administering justice (as part of assizes–a medieval form of our modern juries), manage his estates (which was his prime source of income), and continue to hone his combat skills in tournament.
The tournament in the early Middle Ages (ca. 800-1200 C.E.) was often a meleé, resembling actual combat in groups that could result in injuries or even death. Men were taken hostage and held for ransom, horses and armor confiscated by the captors. As kings and churchmen grew concerned over this senseless loss of life and resources new regulations and safety measures were put into effect. The meleé was replaced by individual combat events (among them the joust), and new innovations in armor specifically designed for the tournament made it somewhat safer.