But why do we speak of it as a coat of arms when there is nothing to suggest such a term?
I will tell you.
In the far-away days of quite another age, heraldry was so closely connected with warlike exploits, and its signs and tokens were so much used on the battle-field to distinguish friends from foes, that each warrior wore his own special badge, embroidered on the garment or surcoat which covered his armour, as well as, later on, upon the shield which he carried into battle.
And this reminds us of the poor Earl of Gloucester's fate at the Battle of Bannockburn. For, having forgotten to put on his surcoat, he was slain by the enemy, though we are told that "the Scottes would gladly have kept him for a ransom had they only recognized him for the Earl, but he had forgot to put on his coat of armour!"
On the other hand, we have good reason to remember that the "flower of knighthood," Sir John Chandos, lost his life because he did wear his white sarcenet robe emblazoned with his arms. For it was because his feet became entangled in its folds (as Froissart tells us) in his encounter with the French on the Bridge of Lussac, that he stumbled on the slippery ground on that early winter's morning, and thus was quickly despatched by the enemy's blows.
"Now, the principal end for which these signs were first taken up and put in use," says Guillim, "was that they might serve as notes and marks to distinguish tribes, families and particular persons from the other. Nor was this their only use. They also served to describe the nature, quality, and disposition of their bearer."
Sir G. Mackenzie goes farther, and declares that heraldry was invented, or, at any rate, kept up, for two chief purposes:
First, in order to perpetuate the memory of great actions and noble deeds. Secondly, that governors might have the means of encouraging others to perform high exploits by rewarding their deserving subjects by a cheap kind of immortality. (To our ears that last sentence sounds rather disrespectful to the honour of heraldry.)
Thus, for example, King Robert the Bruce gave armorial bearings to the House of Wintoun, which represented a falling crown supported by a sword, to show that its members had supported the crown in its distress, while to one Veitch he gave a bullock's head, "to remember posterity" that the bearer had succoured the King with food in bringing some bullocks to the camp, when he was in want of provisions.