A European knight

Heavily armoured knights like this are the familiar image of crusading armies, yet were always a small minority of the men who journeyed to the east to impose the will of the western christian church on the Holy Land.

Modern popular imagery greatly exaggerates the status held by knights of the eleventh to thirteen centuries. Most were merely military retainers of great lords, and often quite poor; perhaps not even owning their own weapons and armour, let alone land, or that great consumer of labour and resources: a cavalry horse. In England up to 1250 a knight could be compelled by his lord to work in the fields with the peasants if the lord required it.

The surcoat, which was derived, like so much else, from long established Middle Eastern fashions, took considerably longer to gain acceptence in military use than amongst civilians in the West for the simple reason that few men of the knightly class were wealthy enough to be able to have a costly garment destroyed each tournament or battle.

Mail leggings, or chausses, had begun to appear in the early eleventh century but did not become common equipment for even the best armed knights until the middle of the twelfth century.
Other aspects of this knight's panoply, such as the separate coif, or hood of mail, and vambraces, forearm protection, while known in the twelfth century, (and still earlier in the Roman world) became more prevalent in European use in the thirteenth century.

Towards the end of the twelfth century open-faced nasal- and pot-helms began to be replaced by more protective helmets covering the face under the influence of practices employed by Romans and others for centuries.

This type of helm, known as “Phrygian”, was one of the most widespread in the twelfth century. It was used by Westerners, Romans and Muslims. The squared ridge across the front of the helm makes it a very rigid shape, more resistant to being cut or crushed.

Heraldry did not attain the systematic personal form known today until the second half of the thirteenth century, but a century earlier very simple forms such as the one carried by the knight above were employed by eminent families to distinguish themselves and their retainers.
Not surprisingly, royalty was ahead of the general trend. This shield is painted with the emblem variously attributed to King Richard I or King John of England.

The fittings of a twelfth and thirteenth century shield were a very practical and adaptible arrangement. On horseback the shield was supported by the long, Narrow strap, or guige. The knight then threaded his left forearm down through the longer central strap of the U. This fixed the shield in position while leaving the left hand free to manage the reins. On foot, the left arm was threaded up though the wide lower band of the U, and the hand grasped the top crossed straps.

Sources

Richard Barber The Knight and Chivalry London 1970
Francis Gies The Knight in History New York 1984
C. Harper-Bill & R. Harvey The Ideals and Practice of Medieval Knighthood II Woodbridge 1988
Christopher Marshall Warfare in the Latin East: 1192 - 1291, Cambridge, 1992
R.C. Smail Crusading Warfare: 1097 - 1193, Cambridge, 1989