Plate, Heavy Three Quarters
This is a heavier, somewhat crude version of three quarters harness which began to appear in the 17th Century, and was designed to be literally bullet-proof. This heavier armor was usually made of iron, and much thicker than earlier 15th Century armor. This remained in limited use by some heavy cavalry and (more rarely) pikemen, (typically officers, bodyguards, or standard bearers) through the 18th Century. By this time the ability to make steel armor had been nearly lost and to compensate this iron armor was so thick that it was significantly heavier than a full panoply was in the early 16th Century. That is why armor of this type was usually only worn by cavalry.