The Romans were the first to develop armor for dragons and used it to fit war dragons. They made it out of strong materials such as bronze and iron. After the fall of the Roman Empire dragon armor was lost to the ages and pieces of it are rare antiques to this day.
Dragon armor normally includes plates for the head, neck and body. It is very hard to fashion armor for the tail, as this requires many different movable parts. Generally the armor is designed of hundreds of overlapping metal plates, covering any vital parts of the dragon including the soft underbelly, which is considered to be the weakest point of a dragon's body.