Shield (knight's)

Most knight's shields during the 14th century were of the familiar "heater" shape, varying widely in size. Knights who are illustrated in tournaments usually carry a very small shield, while those in war often carry a larger one. This owes itself probably to the presence of highly dangerous missle weapons on the battlefield, something the tourneying knight did not have to worry about very often. Also, the tournament carries an element of sport that rarely existed in war, so the small shield might also have served to encourage deeds of aggressive prowess rather than defensive boredom for the gallery.
Like his other accoutrement, the knight's shield came to take on symbolic meaning. A dishonored knight had his spurs hacked off and his shield hung upside down in disgrace, which insinuates that the shield stood for the honor and renown of the knight, which makes sense since his heraldic blazon, the way he was known on the battlefield or tournament list, was known.