Armour, as insurance

Killing knights who were opponents was not necessarily the rule in medieval conflicts. In war, a knight wearing an expensive harness might well be captured rather than killed both because knights tended to see themselves as a more or less homogeneous, almost brotherly class, and also because a rich suit of armour indicated that the knight had money-it was more in the financial interest of the capturing knight to take him alive and demand a ransom than to slay him outright and lose the ransom. Fine armour and horse both contributed to communicating this intent on the battlefield, though it was not always effective, as at Agincourt when more than 1,500 knights were slain outright following the battle.